Chris Cox, the son of state GOP chairman Ed Cox who’s mulling a run for Congress in Long Island, recently switched his voter registration to the Suffolk County district he may try to represent.

Cox resides in Manhattan, where he’d been registered to vote on the Upper East Side, records show. But he recently switched his registration to a Hamptons property his family has in Suffolk County, a source confirms.

Congressional members have to live in the states they serve, but not necessarily their districts. Still, the issue of a “primary” residence in the district is often fodder during campaigns.

Cox is going through the GOP screening process, along with a string of other candidates looking to take on Democrat Tim Bishop — who is seen as vulnerable for a variety of reasons, including the anti-incumbent sentiment sweeping the region.