President Donald Trump's approval rating has dipped to 50 percent in 439 select "surge" and "flip" counties in 16 states that fueled his victory last November, according to the latest NBC News/Wall Street Journal poll, which was released in part Sunday morning.

The presidential approval poll surveyed adults in those "Trump counties" that either flipped from former President Barack Obama or where Trump trumped Mitt Romney's 2012 performance. Of those 50 percent of people who approve, 29 percent do so "strongly," while of the 46 percent who disapprove, 35 percent do so "strongly."

The 16 states polled were: Colorado, Florida, Georgia, Indiana, Iowa, Maine, Michigan, Minnesota, Missouri, Nevada, New Hampshire, North Carolina, Ohio, Pennsylvania, Virginia, and Wisconsin.

The results were also broken down by "flip" and "surge" counties, according to the report.

Counties which flipped from Obama in '12 to Trump in '16:

44 percent approve of Trump's job performance.

51 percent disapprove.

Counties which surged even more toward Trump and the GOP in '16 from Romney in '12:

56 percent approve of Trump's job performance.

40 percent disapprove.

That dichotomy of results suggest Trump has lost ground in counties he was able to flip in his favor this past election.

The poll, in which more results will be released later this week, according to the report, surveyed "adults" and not necessarily "voters." President Trump has long contended polling results do not accurately reflect the voting results and the potential inclusion of illegals in polling would sway results against him, since he is working to fight illegal immigration.

The NBC/WSJ poll surveyed 600 adults from July 8-12 in those 439 counties and has a margin of error of plus-minus 4.0 percentage points.

But even the total poll was tilted toward the counties less favorable to Trump and the GOP. Specific to county type: 342 adults were surveyed in "flip" counties with a 5.3 margin or error, while just 258 adults were polled in "surge" counties with a 6.1 percentage margin of error.