ALBANY - The Hudson Valley is shaping up to be a key battleground in the national fight for control of the House of Representatives in November.

Freshman Rep. John Faso, a Kinderhook Republican, leads his Democratic challenger Antonio Delgado by 45 to 40 percent among likely voters in a Siena Research Institute poll released Thursday night. The lead is within the margin of error 4.8 percent, signaling a potentially tight race.

Read the entire poll on the Capitol Confidential blog.

Siena pollster Steve Greenberg said the five-point lead indicates Faso has "a real race on his hands."

The poll did not factor in Green Party candidate Steve Greenfield.

The 19th Congressional District stretches from the Capital Region into the Hudson Valley and includes all of Columbia, Greene and Schoharie counties, and parts of Montgomery and Rensselaer counties. It also comprises Sullivan, Delaware and Otsego counties and part of Broome County.

Favorable opinions of Faso are split in the district, with the remaining 24 percent remaining neutral. Nearly half of the voters polled don't have an opinion about Delgado, but his favorable rating is 12 percentage points higher than his unfavorable rating.

While Democrats have largely made up their decision about the race, 14 percent of Republicans say they're undecided about their Election Day decision. Faso leads among independent voters by six percentage points.

There is a stark gender divide, with a plurality of women backing Delgado, and Faso winning support of men by 19 percentage points.

Delgado's strength is in the Democratic stronghold of Dutchess and Ulster counties, where the poll results indicate he wins 49 percent. Faso is winning a majority of the voters' support in the Southern Tier and Capital Region.

The district is relatively split on the job President Donald Trump is doing and narrowly prefers having Republicans maintain control of the House of Representatives.

Earlier this month, the race was deemed a "toss up" by separate analysis from CQ Roll Call and FiveThirtyEight.

Delgado, a Schenectady-born attorney who lives in Dutchess County, secured the Democratic nomination after winning a seven-candidate primary in June with 22 percent of the vote. He is also expected to appear on the Working Families and Women's Equality lines.

Faso, the 2006 GOP gubernatorial nominee, is expected to appear on the Republican, Conservative, Independence and Reform party lines.

Discussion around the race this summer has been dominated by advertisements from an outside super PAC supporting Faso, which has highlighted Delgado's past lyrics as a rapper to argue that he's out of touch with the district. Faso has argued the lyrics are fair game and raise important questions, but the attack has drawn accusations of race divisiveness, as Delgado is black and a vast majority of the district is white.

Delgado's campaign has repeatedly focused on Faso's vote last year to repeal the federal Affordable Care Act — or Obamacare — by releasing a series of emotional advertisements featuring district residents.

Democrats have longingly eyed the district since its boundaries were drawn in 2012, and it was represented by freshman Republican Chris Gibson. They failed twice to unseat him, including a disastrous 2014 campaign when Gibson won almost 65 percent of the vote.

Two years later, Faso defeated Democrat Zephyr Teachout, capturing 54 to 46 percent of the vote.

The partisan makeup of the district has shifted slightly since being shaped six years ago, when Democrats accounted for 31 percent and Republicans 33 percent. The district is now 32.4 percent Democratic to 31.7 percent Republican, with Independence Party and unaffiliated voters accounting for nearly 33 percent.

David.Lombardo@timesunion.com - 518.454.5427 - @poozer87