Story highlights Trump's approval is 56% in the counties where he greatly outperformed Mitt Romney

Only 26% of young voters ages 18 to 34 approve of Trump

(CNN) While President Donald Trump's approval rating continues to lag, many of his supporters in the Republican base remain by his side.

In the counties Trump won in November 2016, 50% of adults approve of his job performance, according to a Wall Street Journal/NBC News poll released Sunday. Less than half, 46%, disapprove.

But there is a difference in support for Trump among the counties he easily won versus those that were swing counties.

Trump's approval is 56% in the counties where he outperformed 2012 Republican nominee Mitt Romney by at least 20 points. But in counties that backed former President Barack Obama in 2012 before going for Trump in 2016, the President's approval is just 44%, 7 percentage points lower than his disapproval.

Only 26% of young voters ages 18 to 34 approve of Trump while 70% disapprove. But in counties that backed Trump, 42% of voters in that same age range approve of Trump's job performance while 52% disapprove.

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