Twenty-one people had received citations through Monday for entering Grand Canyon National Park after a partial government shutdown forced its closure, the park's chief ranger says.
Grand Canyon Chief Ranger Bill Wright said some people have been caught attempting hikes or trying to sneak in through dirt roads.
All national parks are closed as a result of the government shutdown.
Arizona political leaders have called on the Obama administration to reopen the Grand Canyon using state money to pay costs of running it. Gov. Jan Brewer has led the call, saying the canyon is important to the state's economy., with an estimated $1.3 million a day spent there by tourists.
Brewer and Arizona House Speaker Andy Tobin complained earlier this week that the administration had turned down the proposal to use state money to reopen the park.
The Grand Canyon's closure may be the most visible effect of the federal closure in Arizona, but it is not the only one.
Civilian workers at military installations were furloughed, including 1,600 at Davis-Monthan Air Force Base in Tucson.
Welfare payments were stopped for the first few days of the shutdown for thousands of poor families.
Public education officials say they are worried that school lunch programs, funded by the federal government, will run out of money by the end of the month.
E-Verify, the federal government's electronic database showing who is legally allowed to work in the country is not functioning. Under Arizona law, employers must check the names of potential employees with E-Verify.