For a few early hours this Sunday, the Southwest Freeway will be the only conduit into or out of the box of land framed by Kirby Dr., Montrose Blvd., Bissonnet St. and W. Gray St. (give or take a traffic peninsula leading up to Allen Pkwy., which will also be closed for much of the morning).
The Houston Marathon will launch from 4 corrals leading to Congress Ave. at San Jacinto St., and loop through the city along the route outlined in black above. The Half Marathon route (outlined in yellow) will pant alongside until just before mile 8, when it will skive off north back toward the shared finish line at Discovery Green.
A larger version of the map is show in 2 parts below, complete with start and end times (in red and green respectively) of each mile marker’s street closure:
