USA. Arizona. January 8, 2019. The count of border wall miles constructed during Trump’s presidency varies based on the method used. According to US Customs and Border Protection data, one tally puts it at 458 miles. However, the majority of these additions involved replacing smaller, deteriorated barriers, making minimal impact on the overall mileage. The “Trump Wall” is estimated to have cost $33 million per mile built. This picture was shot near the Nogales border point in Arizona.