An intrastate route, Interstate 45 joins Houston and the Texas Gulf Coast with the Dallas/Ft. Worth Metroplex. Beginning on Galveston Island, IH 45 replaced U.S. 75 along the Gulf Freeway, a pre-Interstate era highway constructed between Galveston and Houston. Angling northwest, the freeway passes by NASA’s Johnson Space Center toward South Houston, Park Place and Downtown Houston.
Within central Houston, IH 45 briefly runs side by side with IH 10 and U.S. 90. This will further change with the North Houston Highway Improvements Project, which relocates IH 45 into dual freeway configuration with IH 69 / U.S. 59 along the Eastex Freeway along the east side of Downtown. IH 45 will also extend further adjacent to IH 10 north of Downtown before joining the North Freeway to Westfield, Spring, The Woodlands and other northern Houston suburbs.
Beyond Conroe, IH 45 transitions to a rural freeway through Sam Houston National Forest. Exiting the forest, the freeway shifts westward from Huntsville to Madisonville while remaining rural to Coriscana. U.S. 287 combines with the freeway between Corsicana to Ennis, where it branches northwest to Waxahachie, Mansfield and Fort Worth. With increasing industrial development, IH 45 proceeds from U.S. 287 to Ennis, Ferris, Wilmer and south Dallas.
IH 45 concludes at IH 30 and U.S. 75 (Central Expressway) by Deep Ellum and Downtown Dallas. The southern 1.427 miles of U.S. 75 double as unsigned IH 345. Exit numbers continue northward along the IH 345 segment to Spur 366 (Woodall Rogers Freeway), where they reset using a sequential system along the remainder of U.S. 75 northward.
Approved by the Texas State Highway Commission in 1962 with 286 miles, IH 45 was an original Interstate Highway.1 Authorized in 1956, the section of IH 45 in Navarro County near Corsicana represents the first Interstate Highway contract to be let in Texas.2 However, the U.S. 75 / Gulf Freeway portion of IH 45 predated the Interstate system, which opened in September 1948. The Gulf Freeway was fully signed as IH 45 in 1971 following a series of upgrades to Interstate standards.
Construction started on the North Freeway segment of IH 45 in Houston in December 1959. It was completed north to Spring by February 1963. Succeeding sections of IH 45 were completed in the 1960s, including the stretch from Conroe to Madisonville, the section from Madisonville to Centerville, and the bypass around Corsicana.
During the early 1970s, the section from Centerville to Buffalo opened. A 12 mile segment of IH 45 between Fairfield and Streetman in Freestone County opened to traffic on October 13, 1971. Remaining sections, including the relocated Central Expressway in Dallas and the portion of IH 45 connecting Buffalo, Richland and Fairfield, were built in the mid to late 1970s.3