The highway crosses into Grimes County, where it is signed as a west–east route, and passes through Richards before turning to the southwest.

In the county seat of Anderson, FM 149 has a one-block concurrency with SH 90 before resuming its westward course.

FM 149 was created on April 20, 1945 as a short spur between Anderson and Richards inside Grimes County.

Later that year, it was extended twice, to the Montgomery County line on June 6, 1945 and to Deckers Prairie ten days later.

The road was truncated to its current length on October 28, 1988, when the section from the southern terminus at Interstate 45 to FM 1774 was transferred to SH 249.