Officials are also hoping to cut the costs of detaining immigrants
The US government has announced plans to use sites like converted hotels and nursing homes to house some immigrants awaiting processing or deportation.
This is part of an overhaul of the system of detaining immigrants, amid reports of abuses and poor care.
Immigrants would be held according to the risk they posed, Homeland Security Secretary Janet Napolitano said.
Each year, thousands of immigrants are held in US jails, alongside regular prisoners, awaiting deportation.
"This is a system that encompasses many different types of detainees, not all of whom need to be held in prison-like circumstances," Ms Napolitano said.
"These new initiatives will improve accountability and safety in our detention facilities."
At the same time, Ms Napolitano stressed that enforcement of immigration laws would continue "unabated".
The US has been criticised for holding illegal immigrants and asylum seekers in often crowded jails alongside regular prisoners.
There have been accusations that detainees have been denied due process and have received poor medical care.
During 2008, a total of nearly 380,000 people were in custody or supervised by Immigrations and Customs Enforcement (ICE), which is part of the Department of Homeland Security.
The facilities used to house the immigrants are mainly jails and prisons, which also house people awaiting trial and those serving sentences.
On 1 September, 2009, ICE had 31,075 immigrants in detention at more than 300 facilities across the US.
Of these, 66% were subject to mandatory detention and 51% were felons. Of these, 11% had committed violent crimes, while the majority of the population were seen as low risk, a report by ICE says.
The plans for reform, which will be put to Congress, will could also result in savings in the cost of detaining immigrants, which stood at almost $2bn (£1.3bn) in 2008.
Ms Napolitano's department says alternatives like converted hotels and nursing homes would cost about $14 a day, compared to about $100 for detention in jail.
President Barack Obama has spoken of the need for comprehensive immigration reform in the US, where an estimated 12 million undocumented people live and work.
Efforts by his predecessor, George W Bush, to reform US immigration laws collapsed in 2007.