The correct answer would be the United States of America; but if you mean what foreign country, that would be Mexico.
closest national park to san diego?
San Diego Padres
San Diego is the closest, with the San Ysidro and Otay Mesa communities right at the US-Mexico border.
The closest with a baseball team would be San Diego, California. Its local team is the San Diego Padres.
The closest hotel to the Sea World Way entrance to the park is the Holiday Inn Express San Diego, 3950 Jupiter St, San Diego, CA, 92110.
The closest found is - San Diego Civic Light Opera 1549 El Prado San Diego, CA 92101
From San Diego to Evansville, Indiana (the closest part of Indiana to San Diego), is about 29 hours driving, not including stops.
Yuma
Due west of San Diego is Mexico, specifically the Baja California Peninsula. The Pacific Ocean lies directly west of San Diego, but to reach land, one would enter Mexico shortly after crossing the ocean. The closest Mexican city to San Diego is Tijuana, which is located just south of the border.
The closest Mexican beach to San Diego is Playas de Tijuana. It's about 25 miles from downtown San Diego.
The two closest hotels are about the same distance from the stadium: Corporate Suites At Portofino, 2500 Northside Drive, San Diego, CA 92108. Madison San Diego, 2288 Fenton Parkway, San Diego, CA, 92108.
The San Diego Padres are the closest MLB team to Mexico, 10 miles (16 kilometers) away from the US-Mexico border.