"We intend to comply with all federal obligations as they pertain to ICE," Kincaid said in her statement. "We found it expedient to no longer have an agreement that required us to extend our resources beyond these obligations."
Under the contract launched in 2012, the county has kept inmates targeted by ICE for as many as 48 hours beyond their release dates.
Russell Hott, field office director for ICE's Enforcement and Removal Operations Washington, D.C. responded in a statement: "ICE and Fairfax County remain committed to working together to protect public safety and will continue to work together to ensure the safe and orderly transfer of removable aliens to ICE custody pursuant to immigration detainers.
"ICE maintains that immigration detainers serve as a legally-authorized request, upon which a law enforcement agency may rely, to continue to maintain custody of an alien for up to 48 hours so that ICE may assume custody for removal purposes. Although the parties will no longer have a contractual agreement in place for Fairfax County to house ICE detainees, this will not impact cooperation between the parties generally."
Amid a refueled debate over illegal immigration, the agency has stepped up its deportations in recent months, with agents raiding 7-Eleven convenience stores and other work sites.
Last month, Think Progress, a media outlet launched by the progressive Center for American Progress Action Fund, reported that 663 inmates in Fairfax County Jail had been turned over to ICE in 2017, more than double those in 2016. The majority of those people were from El Salvador, Honduras and Guatemala, according to the report, which was based on county public records released under a Freedom of Information Act request.
Following criticism from immigration activists, Kincaid notified ICE on Monday that the county intends to terminate the agreement effective May 23 after a required 120-day notice, according to her statement.
Kincaid said the county will honor an ICE request to detain an inmate only if that request is accompanied by a court-issued criminal detainer, a rare occurrence given that most deportations are conducted as civil court proceedings.
The move drew praise from immigration groups and county leaders, who've walked a fine line between calling Fairfax a welcoming place for immigrants while steering clear of the word "sanctuary," which could spark a backlash from the Trump administration and hard-line immigration groups.
In a statement, Sharon Bulova (D), chair of the county board of supervisors, said she was "pleased" with Kincaid's decision: "The Sheriff and her deputies operate the county jail and are not federal immigration officials."
Simon Y. Sandoval-Moshenberg, director of the Legal Aid Justice Center's Immigrant Advocacy Program in Northern Virginia, called the action "a tremendous step in the right direction."
Sandoval-Moshenberg and other immigration attorneys have fought against ICE holds, arguing that they violate the U.S. Constitution's Fourth Amendment, which protects people from being detained without probable cause.
"It's pretty clear that to hold someone beyond their release date based solely on an ICE detainer violates law," he said. "A lot of people don't believe that having an intergovernmental contract essentially cures that violation of law."