Most at the vigil had no relation to the victims, but they grieved for the senseless loss of life.
As investigators continue to try to determine the gunman's motives, many in the LGBT community came together Sunday night as a show of strength to send a message that hatred will not defeat them.
"Let this by a symbol of our mutual commitment to the entire community, to our nation," Bishop James Wilkowski of the Evangelical Catholic Diocese.
Chicagoan David Jade Sotomayor lost his cousin, 34-year-old Eddie, one of the nightclub victims in Orlando.
"He was amazing," David said. "He was awesome. I called him this morning just to hear his voicemail...it's a little heartbreaking."
Black bunting had been placed at the entrance of one of Chicago's most popular gay nightclubs.
"I want my customers to feel safe because for most of our history the only place that our community felt safe was in a nightclub," said Art Johnson, co-owner of Sidetrack nightclub.
Thousands came out to Andersonville's Midsommarfest, which traditionally attracts many in Chicago's LGBT community.
"I thought am I exposing myself to danger by being at an obviously gay situation," said business owner John Treadwell."
There were visible signs of support for the victims in Orlando, with shopkeepers joining in fundraising efforts and activists donning black armbands.
"There were over 50 mothers who got a phone call this morning saying that their child had been killed simply because they were at a gay club last night in Orlando," said Brian Johnson of Equality Illinois.
Most in Chicago's LGBT community Sunday expressed the hope this hate crime won't be used as an excuse for others.
"We also need to stand together not as Americans but as human beings," said Andy Thayer of the Gay Liberation Network. "We need to understand that all forms of hate are wrong whether against Muslims, whether against gays or whomever.
Members of the Chicago area's Muslim community have also denounced the shooting. The Islamic Society of North Western Suburbs of Chicago released a statement saying, "Our religion does not support or agree with the notion that murder of the innocent yields rewards. We strongly believe that all life is precious, sacred and should be revered....This is clearly an act of terror committed by a man who has nothing to do with true Islam as practiced by the millions of peaceful and law-abiding Muslims of this great country."
Within hours of learning about the nightclub massacre, statements of mourning, sympathy and support began to be issued by local leaders and members of the LGBT community.
Mayor Rahm Emanuel issued a statement, saying:
Last night's horrifying act of terrorism in Orlando was an attack on our most fundamental values as Americans. On behalf of the City of Chicago, Amy and I send our deepest condolences to the friends and family members of those who were lost. June is a time when all Chicagoans and all Americans proudly celebrate the contributions of our LGBT community. This horrendous violence will only deepen our resolve to continue building a society that values everyone, regardless of who they love. The thoughts and prayers of Chicago will remain with the victims of this attack as they seek comfort and courage in the days ahead.
Later Sunday evening, Emanuel sent out another statement saying, "We will not be intimidated by those who use fear and violence to attack our most fundamental values of inclusiveness and community. Two weeks from today I look forward to joining many others in Chicago as we come together as a city to celebrate those values, and the LGBT community, at our Pride Parade."
Police said security will be extremely tight at the Chicago Pride Parade in two weeks.
The Chicago Police Department also issued a statement, saying, "As we learn about another reprehensible act of gun violence, CPD extends our deepest condolences to those affected by the horrible tragedy in Orlando. Our thoughts and support also go out to our partners at the FBI and Orlando Police for their great work managing such a tragic and difficult incident. This morning we reached out to Orlando PD to offer any technical, manpower or resource assistance."
The attack came during LGBT Pride Month and among pride celebrations across the United States. Chicago's Pride Festival is scheduled for June 18 and 19; the Pride Parade is scheduled for June 26. The Office of Emergency Management and Communications released a statement on the Orlando attacks and addressed any concerns about safety at Chicago's Pride celebrations:
Every year, the City's public safety departments work closely with the parade organizers to ensure a safe, secure and enjoyable time for participants, attendees and residents. This year will be no different - and we will not allow the despicable act that occurred in Orlando to diminish Chicago's celebration of our LGBT community at the Pride Parade.
An additional planning meeting has been scheduled for the event and we will continue to adjust and increase resources as necessary.
Our heartfelt thoughts and sympathy are with all of those affected by this senseless tragedy.
LGBT organizations across the city and state have also issued statements of mourning. Equality Illinois wrote, in part, "While we don't know yet the specific motive of the shooter, it is obviously a hateful act. We do know we should all feel safe in our homes, schools and places of business and entertainment. Our hearts go out to the Orlando LGBT community and the family and friends of the victims, and we wish a speedy recovery to the injured."
Non-profit organization Lambda Legal, which often works on and for LGBT rights issues and clients, also issued a statement saying in part, "Our thoughts are with the loved ones of those who were killed and with those who were injured or who witnessed this horrific assault. No more hatred and violence against our community."
U.S. Senator Mark Kirk issued a statement saying, "Our thoughts and prayers go out to the victims of this hateful terrorist act that targeted the Orlando gay community. Gunman Omar Mateen's motivations remind us of the immediate threat the Islamic State poses to our country and the need for swift action to protect Americans from future attacks here at home."
Governor Bruce Rauner ordered flags to fly at half mast.
"It was heartbreaking to learn about the tragic massacre in Orlando, Florida. To target a community in celebration is deplorable. The State of Illinois stands with those in the State of Florida, and in honor of the victims, I am ordering all flags to be lowered to half-staff immediately. Please join me and Diana in praying for all those affected by this senseless tragedy," Rauner said in a statement.
Archbishop Blase Cupich issued a statement saying in part, "The people of the Archdiocese of Chicago stand with the victims and their loved ones, and reaffirm our commitment, with Pope Francis, to address the causes of such tragedy, including easy access to deadly weapons. We can no longer stand by and do nothing."