Voter data from U.S. Election Atlas. Republican candidates for the U.S. House won in the November election among every type of U.S. county except those in the largest metropolitan areas (1 million residents and up). The chart shows each party’s performance in counties categorized using the Rural-Urban Continuum Code — nine categories that move in general terms from the most urban (No. 1) to the most rural (No. 9).

Ask anybody. They’ll tell you that the more rural the place, the more Republican the vote. It’s an axiom of American politics.

We decided to see if this presumption was true, at least in the latest election, the vote for all the seats in the House this past November. And we found this truism — that Republican totals grow with distance from city centers — isn’t true at all.

Yes, rural areas vote Republican. But, it turns out, so do a lot of urban counties. And as the geography gets more rural, there is no distinct rise in Republican vote.

What the results from November show is that we have been looking at the geography of the vote backwards. The most pronounced feature of the electoral landscape is how Democrats have packed themselves into the most urban counties.

Democrats won 53.3 percent of the vote this November in the 438 most urban counties, those that are part of metropolitan areas of more than one million people. These counties had just over half the total vote in November’s election.

In the rest of America, Democrats won only 40.7 percent of the vote for House members.

And, as places got more rural, Republican percentages didn’t rise.

Democrats don’t have a problem getting just rural votes. Democrats have a problem getting votes in urban and rural counties found outside the major metropolitan regions. Rural, urban — it doesn’t seem to matter.

To come to this conclusion we took all the votes for member of the U.S. House of Representatives this November. (Every House district had an election.) The vote was compiled at the county level. (Some counties are split into several House districts.) We used voting data from the U.S. Election Atlas. (The data is preliminary, and the vote from some counties is missing. But the missing data isn’t enough to change our bottom-line results.)

Then we sorted counties according to the U.S. Department of Agriculture’s Rural-Urban Continuum Code, or RUCC.

What in the heck is an RUCC? Well, the USDA sorted all counties (there are 3,143) along a continuum, from most urban to most rural. The USDA’s demographers came up with nine categories. The first three categories contain metropolitan counties, moving from the largest to smallest ones. They are:

1. Counties that are part of metropolitan regions of 1 million or more people. (432 counties.)

2. Counties that are part of metropolitan regions with 250,000 to 1 million people. (379 counties.)

3. Counties that are part of metropolitan regions with fewer than 250,000 people. (356 counties.)

The rest of the counties, in groups 4 through 9, are non-metropolitan. They are sorted into groups that are increasingly rural:

4. Non-metro counties with urban populations of 20,000 or more and adjacent to a metropolitan region. (214 counties.)

5. Non-metro counties with urban populations of 20,000 or more but not adjacent to a metro area. (92 counties.)

6. Non-metro counties with urban populations of 2,500 to 19,999 and adjacent to a metro area. (593 counties.)

7. Non-metro counties with urban populations of 2,500 to 19,999 people and not adjacent to a metro area. (433 counties.)

8. Completely rural counties with less than 2,500 urban population that are adjacent to metro areas. (220 counties.)

9. Completely rural counties with less than 2,500 urban population and not adjacent to a metro area. (424 counties.)

(To see a complete explanation of RUCC, go here.)

Now the chart above should make sense. We totaled the vote (Republican and Democratic) by RUCC, one through nine. Red bars show the percent of the Republican vote in each category; blue shows the percent of Democratic votes in each category.)

You can see that Democrats scored big in RUCC #1, the counties in the nation’s most populous urban areas, winning 53.3 percent of the vote. Democrats do well nationally because these counties had just over half the total vote in November.

But in every other category — urban and rural — Democrats lost by 10 percentage points or more.

Yes, the most rural category (9) is also the most Republican. But category 8 is less Republican than category 3, a group of metropolitan counties.

There is really no discernable pattern. Except: Democrats do well in the biggest of cities; in the rest of the country, Republicans win by landslide numbers.

The outlier here geographically has nothing to do with how rural a place might be. The question is why Republicans don’t do better in major metropolitan areas — and why Democrats do well ONLY in the biggest cities.