Donald Trump has built his campaign on the support of working-class white voters and hopes his appeal with the group will propel him to the presidency in November presidential elections.
Trump's focus against trade deals and pledges to bring jobs back to the United States seem tailored to a region stretching from western New York into Michigan along the Great Lakes, where manufacturing jobs have declined in recent decades.
Republicans attending the centre-right party's convention in Cleveland, Ohio, itself part of the so-called Rust Belt, think Trump has what it takes to succeed in the region.
They believe he can even win in states like Pennsylvania, which has not voted for a Republican presidential candidate since George HW Bush in 1988.
"There is a lot of appeal for Donald Trump" in Pennsylvania "because he's a different kind of candidate," delegate Caroline Welsh told dpa.
Congressman Glenn Thompson said he saw a lot of opportunity for Trump to win in Pennsylvania after his successful showing in the state's primary.
Trump appeals to Rust Belt voters, including union members, coal miners, natural gas workers and others who are "just disenfranchised from the liberal Democrats of Hillary Clinton," Thompson said.
A Quinnipiac University poll released last week showed Trump narrowly leading Clinton in Pennsylvania and said the rivals were tied in the neighbouring key swing state of Ohio. However an average of recent polls by website Real Clear Politics gives Clinton an edge in those states.
Indiana Governor Mike Pence projected Midwestern values when he accepted the party's vice presidential nomination on Wednesday. He said that Trump appealed to many voters who traditionally were Democrats.
"It will be our party and our agenda that opens the doors for all Americans to succeed and prosper," he said, noting the Democratic Party had abandoned those it used to protect.
Ohio Republican staffer Katie Eagan said Trump can win Ohio and has already been receiving support in areas of the state that traditionally vote for Democrats.
The state's primary saw 150,000 new Republican voters, and the party will focus on turning them out in November, Eagan said.
But Trump's unpopularity with minority voters means he will have to win a larger share of white voters than previous Republicans, University of Virginia election analysts Kyle Kondik and Geoff Skelly said, noting he also has trouble with more educated whites.
"Maybe Trump's path to victory goes through the whiter Midwest," Kondik said. "But there isn't any indication that he has a special appeal in those places."
Kondik notes no Republican has won the White House without the support of Ohio, while Skelly said "Pennsylvania is something Republicans reach for but can never quite grab."
Pennsylvania delegate Welsh however hopes that will be different this time around.
"This is a different kind of movement and Donald Trump is the man behind that movement," she said, pointing to new voters who "don't know what's wrong with America, but know it's not working right."
Fellow Pennsylvanian Ash Khare, an Indian immigrant and Trump supporter, agrees, noting the Republicans in his district overwhelmingly supported Trump, who "tapped into a real problem of this country."
"We're going to clean house. The best days of the US are before us," he said.