Gov. Andrew Cuomo made an unscheduled visit to the state Democratic Party’s meeting Sunday evening in Rye Brook and announced he is backing party candidates “across the board” next month.

The blanket endorsement includes supporting candidates in the range of contests in November, including the mayoral and county executive candidates in competitive races.

Cuomo has previously endorsed Democratic mayoral nominee Bill de Blasio. In the large upstate cities — Albany, Buffalo, Rochester and Syracuse — Democrats are either running unopposed or are considered heavy favorites.

It’s on the county level — especially the suburban counties — where the endorsement of the state’s top Democrat may count the most.

In Westchester, Republican incumbent Rob Astorino is running for a second term against Democratic New Rochelle Mayor Noam Bramson.

Astorino, who has a wide lead in fundraising, is considered a potential Republican candidate for governor in 2014.

In Nassau County, Democrat Tom Suozzi is running for his old job against County Executive Ed Mangano.

Cuomo has by all accounts a good working relationship with Mangano.

The appearance before the state Democrats Sunday evening comes nearly a year before Cuomo runs for re-election and will likely focus on the state’s suburban swing counties.

“The Governor announced that he is supporting Democrats across the board statewide in county executive and mayoral races,” said Cuomo spokesman Matt Wing. “He told attendees that we have to work hard through November to get our fellow Democrats elected, take a break in December and then come right back in January ready to fight for Democrats in 2014.”