Here are some of their stories.
She viewed her school as a model, telling The Newtown Bee in 2010 that "I don't think you could find a more positive place to bring students to every day." She had worked to make Sandy Hook a place of safety, too, and in October, 47-year-old Hochsprung shared a picture of the school's evacuation drill with the message "Safety first."
When the unthinkable came, she was ready to defend. Officials said she died while lunging at the gunman in an attempt to overtake him.
"She had an extremely likable style about her," said Gerald Stomski, first selectman of Woodbury, where Hochsprung lived and had taught. "She was an extremely charismatic principal while she was here."
Robbie Parker said his daughter Emilie was artistic and was always quick to draw a picture or make a card for friends. He says the world is a better place because Emilie was in it.
Parker was among the first parents to speak about the loss of one of the 20 children who died in Friday's shootings in Newtown. He struggled to collect his breath at first, much less to speak. He says he's not mad, and expressed sympathy for the shooter's family.
Soto was graduated from Eastern Connecticut State University with a degree in Elementary Education and History, and was attending Southern Connecticut State University for her Masters degree in Special Education.
She had a passion for learning, and loved spending time with her brother, sisters, cousins, and her black lab Roxie.
Investigators told relatives she was killed while shielding her first-graders from danger. She reportedly hid some students in a bathroom or closet, ensuring they were safe.
"You know that when danger arrived in the halls of Sandy Hook elementary, the school staff did not flinch, they did not hesitate. Dawn Hocksprung, Mary Sherlach, Vicki Soto, Lauren Russeau, Rachel Davino, and Anne Marie Murphy -- they responded as we all hope we might respond in such terrifying circumstances."
Mr. Obama signed a photo of Vicki Soto with the inscription, "We will always remember you, Victoria."
"He really made us feel like she was a hero, and that everyone should know it," Vicki's younger brother, Carlos, told CBS News.
Janet Robinson, the superintendent of Newtown Public Schools, said Sherlach and the school's principal ran toward the shooter. They lost their own lives, rushing toward him.
Even as Sherlach neared retirement, her job at Sandy Hook was one she loved. Those who knew her called her a wonderful neighbor, a beautiful person, a dedicated educator.
Her son-in-law, Eric Schwartz, told the South Jersey Times that Sherlach rooted on the Miami Dolphins, enjoyed visiting the Finger Lakes, relished helping children overcome their problems. She had planned to leave work early on Friday, he said, but never had the chance. In a news conference Saturday, he told reporters the loss was devastating, but that Sherlach was doing what she loved.
"Mary felt like she was doing God's work," he said, "working with the children."
The girl's grandmother, Elba Marquez, said the child's family moved to Connecticut just two months ago, drawn from Canada, in part, by Sandy Hook's pristine reputation. The grandmother's brother, Jorge Marquez, is mayor of a Puerto Rican town and said the child's 9-year-old brother was also at the school, but escaped safely.
Elba Marquez had just visited the new home over Thanksgiving and finds herself perplexed by what happened.
"It was a beautiful place, just beautiful," she said. "What happened does not match up with the place where they live."
"It was the best year of her life," she told the Danbury News-Times, where she is a copy editor.
Rousseau has been called gentle, spirited and active. She had planned to see "The Hobbit" with her boyfriend Friday and had baked cupcakes for a party they were to attend afterward. She was a Danbury native, a graduate of the University of Connecticut and the University of Bridgeport, a lover of music, dance and theater.
"I'm used to having people die who are older," her mother said, "not the person whose room is up over the kitchen."
"I will miss your perpetual smile, the twinkle in your dark blue eyes, framed by eyelashes that would be the envy of any lady in this room," Noah's mother, Veronique Pozner, said at the service, according to remarks the family provided to The Associated Press. Both services were closed to the news media.
"Most of all, I will miss your visions of your future," she said. "You wanted to be a doctor, a soldier, a taco factory manager. It was your favorite food, and no doubt you wanted to ensure that the world kept producing tacos."
She closed by saying: "Momma loves you, little man."
Dan Merton, a longtime friend of the girl's family, said he could never forget the child, and he has much to say when he thinks of her.
"She loved attention," he said. "She had perfect manners, perfect table manners. She was the teacher's pet, the line leader."
On Friday, Merton said, she was simply excited to go to school and then return home and make a gingerbread house.
"Her only crime," he said, "is being a wiggly, smiley 6-year-old."
It was the last outfit the outgoing six-year-old redhead would ever pick out. Charlotte's older brother, Guy, was also in the school but was not shot.
Her parents, JoAnn and Joel, had lived in Newtown for four or five years, JoAnn's brother John Hagen, of Nisswa, Minn., told Newsday.
"She was going to go some places in this world," Hagen told the newspaper. "This little girl could light up the room for anyone."
"You couldn't think of a better child," Grimes said.
Grimes' own five children all attended Sandy Hook, too. Cars lined up outside the Kowalskis' ranch home Saturday, and a state trooper's car idled in the driveway. Grimes spoke of the boy only in the present tense.
"Jessica was our first born. She started our family, and she was our rock. She had an answer for everything, she didn't miss a trick, and she outsmarted us every time. We called her our little CEO for the way she carefully thought out and planned everything. We cannot imagine our life without her.
"We are mourning her loss, sharing our beautiful memories we have of her, and trying to help her brother Travis understand why he can't play with his best friend. We are devastated, and our hearts are with the other families who are grieving as we are."
"We are greatly saddened by the loss of our beautiful daughter, Catherine Violet, and our thoughts and prayers are with the other families who have been affected by this tragedy," Jennifer and Matthew Hubbard said.
"We ask that you continue to pray for us and the other families who have experienced loss in this tragedy."
Remembering their daughter, Anne Marie's parents had no shortage of adjectives to offer Newsday: A happy soul. A good mother, wife and daughter. Artistic, fun-loving, witty and hardworking.
When news of the shooting broke, Hugh and Alice McGowan waited for word of their daughter as hours ticked by. And then it came: Authorities told the couple their daughter was a hero who helped shield some of her students from the rain of bullets.
As the grim news arrived, the victim's mother reached for her rosary. "You don't expect your daughter to be murdered," her father told the newspaper. "It happens on TV. It happens elsewhere."
He was born four weeks before his due date, and his family often joked that he came into the world early because he was hungry.
They wrote in his obituary that 6-year-old James, fondly called "J," loved hamburgers with ketchup, his Dad's egg omelets with bacon, and his Mom's french toast. He often asked to stop at Subway and wanted to know how old he needed to be to order a footlong sandwich.
He was a loud and enthusiastic singer and once asked, "How old do I have to be to sing on a stage?"
His family recalled that he was an early-riser who was always ready to get up and go. He and his older sister were the best of friends. He was a thoughtful and considerate child, recently choosing to forgo a gift for himself and use the money to buy his grandfather a mug for Christmas.
Dylan's family, including his English father, American mother and older brother, had moved from southern England to Connecticut in January 2011.
A former neighbor of the Hockley family told Reuters of a feeling of devastation upon hearing the news: "Heard about the tragedy when it happened. To be honest slightly brushed it off - these things happen in America. Got a phone call from a neighbor this morning explaining that the young boy was involved, can't believe it. It suddenly brings it back into focus that yes, it is a tragedy, and they are all so young as well."
D'Avino was a behavioral therapist who had only recently started working at Sandy Hook Elementary School, where she was killed, according to Lissa Lovetere Stone, a friend who is handling her funeral planned for Friday. D'Avino's boyfriend, Anthony Cerritelli, planned to ask her to marry him on Christmas Eve, Lovetere Stone said.
Lovetere Stone said she met D'Avino in 2005 when D'Avino was assigned to her son, who has autism, in their town of Bethlehem. D'Avino was so dedicated she'd make home visits and constantly offered guidance on handling situations, such as helping her son deal with loud music at a wedding.
"Her job didn't end when the school bell rang at 3 o'clock," Lovetere Stone said.
Police told her family that she shielded one of the students during the rampage, Lovetere Stone said.
"I'm heartbroken. I'm numb," Lovetere Stone said. "I think she taught me more about how to be a good mother to a special needs child than anyone else ever had."
Former neighbor Sinde Candella wrote on Facebook that Josephine's parents, Bob and Michelle, are loving and "very into doing things with their girls."
According to a Wall Street Journal article, Josephine liked to ride her bike in the street and set up lemonade stands.
Her family said they won't let the tragedy define Joey's life. They have established Joey's Fund, through the Doug Flutie, Jr. Foundation for Autism as a way to "honor her inspiring and generous spirit." The proceeds will help families raising autistic children.
"It's our way of dealing with this pain and never letting go of her love," they said in the statement.
"We knew we wanted a piece of lawn, somewhere quiet, somewhere with good schools," Francine Wheeler told the Newtown Bee in a profile.
She is a music educator and singer-songwriter. Sometimes the musical mother would try out tunes on her own children, with some tunes that she made up for Ben as a baby eventually finding their way onto a CD, she told the newspaper.
Benjamin's father, David, a former film and television actor, writes and performs still, according to a profile on the website of the Flagpole Radio Cafe theater, with which he's performed in Newtown.
The family are members of Trinity Episcopal Church, whose website noted that Nate - also a student at Sandy Hook Elementary School - was not harmed in Friday's shooting.
New York Giants wide receiver Victor Cruz said he talked to Pinto's family, which is considering burying the 6-year-old boy in Cruz's No. 80 jersey.
Cruz honored Jack Sunday on his cleats, writing on them the words, "Jack Pinto, My Hero" and "R.I.P. Jack Pinto." "I also spoke to an older brother and he was distraught as well. I told him to stay strong and I was going to do whatever I can to honor him," Cruz said after the Giants' game with the Atlanta Falcons. "He was fighting tears and could barely speak to me."
Cruz said he plans to give the gloves he wore during the game to the boy's family, and spend some time with them. "There's no words that can describe the type of feeling that you get when a kid idolizes you so much that unfortunately they want to put him in the casket with your jersey on," he said. "I can't even explain it."
He was the youngest of three children, and in a statement to the media, his family said Daniel earned his missing two front teeth and ripped jeans.
"Words really cannot express what a special boy Daniel was. Such a light. Always smiling, unfailingly polite, incredibly affectionate, fair and so thoughtful towards others, imaginative in play, both intelligent and articulate in conversation: in all, a constant source of laughter and joy," the family said.
She was described by her family as a kind-hearted little girl who formed special bonds with almost everyone she met. Allison would surprise her family with her random acts of kindness - once even offering her snacks to a stranger on a plane, her family recalled.
She loved her teachers and her family. Sometimes, she'd make her parents laugh so hard they cried.
"Allison made the world a better place for six, far too short, years and we now have to figure out how to move on without her," her family said in a statement. "She was a sweet, creative, funny, intelligent little girl who had an amazing life ahead of her. Our world is a lot darker now that she's gone. We love and miss her so much."
The curly-headed little girl loved a lot of things - horses, Harry Potter, the color red. After watching the Disney movie "Brave," she even tried archery.
In a blog called Avielle's Adventures, Richman would tell friends about their family life: trips to Iowa and to the Thanksgiving Day parade in Stamford, and Arielle's 6th birthday at the horse stable, where she was taking horseback riding lessons.
"Today is Avielle's sixth birthday," her dad wrote. "I know that every parent says this, but holy cow, I can't believe how fast the time flies!"
In August, he wrote about the newest milestone for his "little hummingbird," who was about to start first grade at Sandy Hook. "We can't believe it," he wrote. "Jenn and I are both very nervous and excited."
Hsu, 6, was shy and quiet - but she would light up around dogs. Karen Dryer, who lived on the same street as the Hsu family, would see Madeleine's mom waiting for her at the bus stop at 3:15 every afternoon. Dryer would wait too, for her son Logan, who is in kindergarten. Dryer usually brought the family's golden retriever with her.
"She would come off the bus and her face would light up when she saw the dog," Dryer said. Her mom would give her a big squeeze, and Madeleine would hug her little sister. "She was just an absolute doll," Dryer said.
"She seemed very shy, but she was just so sweet."