It then crosses over the Fred Hartman Bridge over the Houston Ship Channel which carries SH 146 traffic.

Spur 201 was designated on December 17, 1941, from SH 146 in Black Duck Bay to Main Street.

On September 23, 1959, Spur 201 was redesignated as Loop 201 and was extended to SH 146 at McKinney Road.

SH 146 begins at its southern terminus at Interstate 45 in Bayou Vista, running concurrent with Loop 197 for about 0.5 miles (0.80 km).

The route then interchanges SH 225 before crossing at the Fred Hartman Bridge over the Houston Ship Channel; from 1953 to 1995, SH 146 crossed under the Houston Ship Channel via the Baytown Tunnel.

In Baytown, the highway forms one of its business routes and then interchanges SH 330 before looping east.

It intersects US 190 before reaching its northern terminus at US 59 (future Interstate 69 corridor).