You won't find one single answer. To get an accurate estimate, you should:
* Specify the model year: Gas mileage has changed over the years.
* Specify the trim level: Different trims have different features that can impact fuel economy.
* Check the EPA's website: The official EPA fuel economy estimates are the most reliable source. Search for "[Year] Jeep Wrangler 4-cylinder EPA fuel economy" on their site (fueleconomy.gov).
Generally speaking, expect a 4-cylinder Jeep Wrangler to get somewhere in the range of 18-25 mpg combined (city and highway). However, this is a broad range, and the actual mileage could be higher or lower.