There are cities roughly 1,000 miles east of San Diego — the original answer was incorrect.
San Diego (32.7° N, 117.2° W). A 1,000-mile (1,609 km) great-circle radius eastward reaches:
San Antonio, Texas is the nearest major metro to the 1,000-mile-east mark.
Jacksonville, FL is ~2,400 miles east — the furthest east in the contiguous US, not the 1,000-mile point. The original answer conflated "furthest east" with "1,000 miles east."