Texas State Highway 146

Business State Highway 146-D (formerly Loop 410) is a business loop that runs from SH 146 in La Porte to Spur 501. The highway was designated on December 1, 1971 as Loop 410 from SH 146 east, north, and west to SH 146, and was marked as a business route of SH 146. On July 28, 1977, the section from SH 146 via Fairmont Parkway to Spur 501 was cancelled, and Loop 410 was rerouted replacing part of Spur 501 and all of Spur 498. Loop 410 was redesignated as Business State Highway 146-D on June 21, 1990.[5][6] On March 26, 2009, the section from Spur 501 via Broadway Street north to Main Street and west via Main Street to SH 146 was given to the city of La Porte.

The original Loop 410 was designated on October 5, 1960, replacing part of Loop 13 from I-410 and I-10 (which replaced the portion of Loop 13 from I-10 to US 90 as this portion of Loop 13 was upgraded to Interstate standards) to I-35. On July 31, 1969, Loop 410 was redesignated as an extension of I-410 as Loop 410 was upgraded to Interstate standards already and so that I-410 could become a full loop.

Business State Highway 146-E is a business loop that runs from SH 146 through Baytown to SH 146. On March 28, 1996, SH 146 was relocated in Baytown replacing Loop 201, and the old route of SH 146 was redesignated as Business State Highway 146-E.