The moves were an attempt by Immigration and Customs Enforcement to get its detainee population in line with what it could afford. The released immigrants still face deportation but will not be held while awaiting their court dates.
Some in Congress said ICE should have explained beforehand that there wasn't enough money to keep everyone in detention.
The immigrants and their lawyers say they were released with little notice or instruction beyond being told to check in periodically.
In many cases, the immigrants were dropped off in the middle of the night at bus stations or airports in metropolitan centers without money to finish their journey home. In Florida, some were released from a facility bordering rural swamp land outside Miami.
Critics argue the plan allowed the release of thousands of criminals without regard to public safety, but officials say almost all the detainees were characterized as low risk. ICE Director John Morton told a congressional panel that 10 of the 2,228 people were the highest level of offender.
"In reducing detention levels, we took careful steps to ensure that national security and public safety were not compromised," he told a congressional hearing.
Meanwhile, the Obama administration, in the midst of trying to get immigration overhauled, switched from daily declarations that the border was secure to warning of the increasingly dire consequences of cutting $754 million from Customs and Border Protection's $12 billion budget.
In the first week of the cuts, some agents in South Texas reported a spike in arrests of immigrants who said smugglers told them they would be briefly detained and then released. The agents' union quickly spread word of a "tidal wave" of immigrants taking advantage of the situation.
Several immigrants interviewed at a migrant shelter in Reynosa, Mexico, across the border from McAllen, Texas, said they had not heard anything suggesting now was a particularly good time to cross. Instead, several said they were returning home because the drug cartel that controlled river crossings made it too expensive and dangerous.