With one week remaining until the Arizona and Michigan primaries — and with the CNN debate in Mesa a day away — the GOP hopefuls are spread out across three different parts of the country.

Former Massachusetts governor Mitt Romney (R) speaks at an event in Cincinnati, Ohio, on Monday. (Mark Lyons/Getty Images)

The event comes as Romney is ratcheting up his criticism of former senator Rick Santorum’s (R-Pa.) record in Washington. It also comes as Romney is looking to head off a win in his home state by his primary rival for the GOP nod.

Santorum, who made a three-stop swing through western Michigan on Monday, is headed to Arizona today, where he’ll address the Maricopa County Lincoln Day Luncheon in the afternoon.

Expected to be in attendance is Joe Arpaio, the embattled Maricopa County sheriff who had endorsed Texas Gov. Rick Perry (R) before Perry dropped out of the race. It will be worth watching whether Arpaio, who is known for his strong anti-illegal immigration stance, makes any new endorsements this time around.

Rep. Ron Paul (R-Texas) takes a day off the trail today, and former House speaker Newt Gingrich (R-Ga.) is spending a second day in a row in Oklahoma.

Here’s a closer look at today on the trail (Courtesy of candidate schedules and the PBS NewsHour Political Calendar; all times Eastern):

11 a.m.: Mitt Romney holds a town hall at Eagle Manufacturing in Shelby Township, Mich.

11 a.m.: Newt Gingrich addresses the Oklahoma State Legislature in Oklahoma City.

1:30 p.m.: Rick Santorum addresses the Maricopa County Lincoln Day Luncheon in Phoenix, Ariz.

7:30 p.m.: Rick Santorum holds a rally in Phoenix, Ariz.