reports for the Los Angeles Times. Researchers said they "don’t know why the teen birth rate was lower—and falling faster—in large urban areas than in rural ones. They did not study abortion rates between 2007 and 2015, nor did they examine whether schools in some counties were more or less likely to promote the use of birth control, or abstinence."
States have county-by-county data on teen births. For example, here are Kentucky data.