For example: http://www.webcitation.org/5jPWyaCDq
In a major rebuke to President Barack Obama, the Senate voted overwhelmingly on Wednesday to block the transfer of Guantanamo detainees to the United States and denied the administration the millions it sought to close the prison. The 90-6 Senate vote—paired with similar House action last week—was a clear sign to Obama that he faces a tough fight getting the Democratic-controlled Congress to agree with his plans to shut down the detention center and move the 240 detainees.
That's from 2009, but it's been an ongoing problem with defense funding bills since then.
This section of the Wikipedia article does an excellent job of explaining President Obama's actions to close the detention camp, and how Congress interfered. They've made it impossible for the President to lawfully transfer the detainees to any US state or foreign country. There is realistically no way for the President to release them without being able to transfer them.
https://en.wikipedia.org/wiki/Guant%C3%A1namo_Bay_detention_...
Can you substantiate your claim that Congress is responsible for this?
Seems like Obama is the Commander in Chief and is the head of the Executive branch...