Undocumented immigrants are applying for the temporary right to live and work openly in the US, as a sweeping immigration policy reform takes effect.
Up to 1.7 million people could be eligible for the programme, unveiled in June by President Barack Obama amid pressure from Hispanic voters.
Republicans say Mr Obama has passed over Congress - and unemployed US citizens - with the programme.
The Latino vote could be important in November's presidential election.
Most of the estimated 11.5 million undocumented immigrants in the US are from Latin America.
'Tapping talent'
Illegal immigrants are getting their records in order as the Department of Homeland Security (DHS) starts accepting applications for the programme, which would allow them to remain and work for at least two years.
Long queues of migrants wanting to submit applications were seen outside immigration offices in parts of the US with large minority populations, such as the states of California and Texas.
In an internal document, DHS officials estimated 1.04 million people would apply in the first year.
The Migration Policy Institute and the Pew Hispanic Center have estimated as many as 1.7 million people could be eligible under the programme.
The administration's plan is to stop deporting many illegal immigrants who were brought to the US as children.
To be eligible, immigrants must prove they arrived in the US before they turned 16, are 30 or younger, have been living here at least five years and are in school or graduated or served in the military.
