Daily Kos Elections recently completed calculating the 2016 presidential election results by congressional district. With ticket-splitting rates at historic lows, and presidential results highly correlated with congressional results, these numbers serve as a strong predictor of future House election outcomes. Consequently, as Democrats look to gain the 24 seats necessary to obtain a House majority, the 23 Republican-held congressional districts that voted for Hillary Clinton are a logical place to start.

As shown on the map above (see here for a larger version), most of these districts are located in upscale suburbs, particularly in Sun Belt states like California and Texas. Several of these seats have substantial Latino populations, while most also have many highly educated white voters who long leaned Republican before they revolted against Donald Trump. White voters have strongly polarized by education level in recent elections, with those holding a college degree increasingly voting Democratic at much higher rates than those who lack a four-year degree. If that trend persists, Trump could remain very unpopular in these suburban districts, giving Democrats an opening downballot.

But while this is a good initial target list, congressional Republicans significantly outran Trump’s performance in these districts. What’s more, 15 of these 23 seats had previously voted for Mitt Romney in 2012, indicating that voters in many of them were comfortable with Republicans who were more mainstream than Trump. And just three of these Republicans won by less than 5 percent in 2016, while only another four prevailed by less than 10 percent. However, given the declining rate of split-ticket outcomes nationally, many of these incumbents could simply be on borrowed time.

You can find a chart of all 23 Clinton-Republican districts below. Be sure to check out our previous maps and analysis of the presidential and congressional results for all the districts, and also our Congress guide spreadsheet, which compiles those results along with demographics and member information for every seat.