Interstate 45


An intrastate route, Interstate 45 joins Houston and the Texas Gulf Coast with the Dallas/Ft. Worth Metroplex along the former route of U.S. 75. Beginning on Galveston Island, IH 45 replaced U.S. 75 along the Gulf Freeway, a pre-Interstate era route 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, the route briefly runs side by side with Interstate 10 and U.S. 90. IH 45 ventures north from there to North Houston, Aldine, Spring and other northern Houston suburbs.

Beyond Conroe, Interstate 45 transitions to a rural freeway through Sam Houston National Forest. Exiting the forest, the freeway turns more west from Huntsville to Madisonville while remaining rural through to Coriscana. Increasingly busy, IH 45 proceeds from there to Ennis, Ferris, Wilmer and Downtown Dallas.

The northern terminus of Interstate 45 is at the southern terminus of Interstate 345, which is signed as the southernmost portion of U.S. 75. An exit numbering anomaly occurs here. The exit numbers of I-45 continue northward along U.S. 75 and the hidden I-345 to the Woodall Rogers Freeway (Texas Spur 366), approximately 1.4 miles north of Interstate 30. Traveling southbound on U.S. 75, the Woodall Rogers Freeway is signed as Exit 1A. Just beyond the ramp to Spur 366, U.S. 75 encounters Exit 285 to Ross Avenue. The IH 30 junction is signed as Exit 284A.1

Future Aspirations

A section in the ISTEA (1991) legislation indicates that U.S. 69 will become part of the Interstate highway system once it is up to Interstate standards; the most logical designation would be Interstate 45, assuming that the highway connects to U.S. 75 in southern Oklahoma. This is taken from ISTEA Section 1074, Designation of United States Route 69, which states, "Notwithstanding any other provision of law, upon the request of the Oklahoma State highway agency, the Secretary shall designate the portion of United States Route 69 from the Oklahoma-Texas State line to Checotah in the State of Oklahoma as a part of the Interstate System pursuant to section 139 of title 23, United States Code." A current plan is to construct a new segment of the Oklahoma Turnpike along the U.S. 69 corridor to bring it to corridor standards.


In Texas, Interstate 45 was an original Interstate Highway, and it was approved by the Texas State Highway Commission in 1962 with 286 miles.2 IH 45 was the recipient of the first Interstate Highway contract to be let in Texas; it was authorized in 1956 to complete a section in Navarro County near Corsicana.2 However, the first section of Interstate 45 to be built was the U.S. 75 / Gulf Freeway segment, which opened in September 1948. After being upgraded to Interstate standards, the Gulf Freeway was signed as IH 45 in 1971. The North Freeway segment of Interstate 45 in Houston started construction in December 1959 and was completed (north to Spring) by February 1963.

Additional sections of Interstate 45 opened in stages: during the 1960s, sections opened included 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. The final gap of rural freeway was opened on October 13, 1971, between Fairfield and Streetman in Freestone County along a 12-mile section. Remaining sections opened in the mid to late 1970s included the relocated Central Expressway in Dallas and the stretch of IH 45 connecting Buffalo, Richland and Fairfield.3

Highway Guides

Southern Terminus - Texas 87 - Galveston, Texas
Perspective from Interstate 45 south
The final two interchanges of Interstate 45 southbound, Exit 1B at 71st Street and Exit 1A with Texas Spur 342/61st Street. Traffic interests to the Galveston beaches partition between 61st Street for West beaches and Texas 87/Broadway Avenue for the East beaches ahead. Photo taken by Chris Patriarca (06/22/03).
Exit 1A departs for Texas Spur 342 southbound. The small airport placard above refers to Galveston International Airport - Scholes Field, accessible from Jones Drive via 61st Street. One half mile of Interstate 45 remain, as the freeway progresses eastward to Texas 87. Photo taken by Chris Patriarca (06/22/03).
Traffic light warning sign on Interstate 45 southbound as traffic from 61st Street northbound merges. Ahead Texas 87 begins and follows Broadway Avenue to the east end of the island. Photo taken by Chris Patriarca (06/22/03).
The aforementioned traffic signal and the zero milepost of Interstate 45. Texas 87 links Galveston Island to the Bolivar Peninsula and Port Bolivar via a auto ferry. The state route is part of a longer coastal route that normally travels to High Island and Sabine Pass. Beach erosion however, has taken its toll on Texas 87 and washed away the routing between High Island and Sabine Pass. Therefore motorists must travel northward via Texas 124 to Interstate 10 Exit 829 and Texas 73 to continue east. Photos taken by Chris Patriarca (06/22/03).
Perspective from Interstate 45 north
Fallen milepost 0 and the first sign bridge for Interstate 45 in Galveston. Texas 87 transitions into Interstate 45 at this point. Exit 1A connects to 61st Street/Texas Spur 342. This highway leads to the Gulf of Mexico waterfront and Seawall Boulevard. Exit 1C connects to Texas 275/Harborside Drive, a road straddling the southern shoreline of Galveston Bay. Top photo taken by Jeff Royston (04/01); bottom photo taken by Chris Patriarca (06/22/03).
Interstate 45 mainline shot of the above Pictured sign bridge. Texas Spur 342 in conjunction with Texas Farm to Market Road 3005 provides a coastal route from Galveston southwestward to Jamaica Beach, Sea Isle, Surfside Beach, and ultimately Freeport. Photos taken by Chris Patriarca (06/22/03) and Jeff Morrison (12/30/05).
Mileage sign at the beginning of Interstate 45 Northbound. Texas City and La Marque are the first mainland communities Interstate 45 encounters. They are accessible from Exit 7 to the north of Galveston Bay. The freeway will encounter the Sam Houston Tollway outside of Houston in 32 miles. Photo taken by Jeff Royston (04/01).
Northern Terminus - Interstate 30 and Interstate 345 & U.S. 75 - Dallas, Texas
Perspective from Interstate 45 north
Interstate 45 ends/U.S. 75 northbound (begins) sign bridge for the northern terminus at Interstate 30. U.S. 75 sees its southern terminus at the same interchange, as it was overtaken by Interstate 45 from Dallas south to Galveston. Photo taken by Brian LeBlanc / Marc Welby (03/01).
Another perspective of the northbound Interstate 45 ends sign bridge Pictured above. Note that TxDOT prefers to use 3-di width shields for their 2-di Interstates. Downtown Dallas is encircled by Interstate 345, Interstate 30, Interstate 35E, and unsigned Texas Spur 366 (connector between Interstate 35E and Interstate 345). Photo taken by Justin Cozart (12/02).
The predecessors and original button copy signage that once graced the sign bridge displayed in the above photograph. Noted that in addition to the sign replacement, the overhead lighting fixtures were removed as reflective signage was installed. Vidcap taken 01/96.
Interstate 30 button copy overheads for Exit 284 along Interstate 45 northbound approaching the terminus. An imprint from removed U.S. 80 shields can be seen to the right of the Interstate 30 shields in these button copy panels. Towards the end of its existence, U.S. 80 overlapped with Interstate 30 through downtown Dallas. Signage here is also a thing of the past now. Vidcap taken 01/96.
Perspective from Interstate 345 & U.S. 75 south
The Interstate 345 designation applies to the U.S. 75/Central Expressway between Interstates 30/45 and unsigned Texas Spur 366/Woodall Rogers Freeway. Otherwise, U.S. 75 extends as a freeway northward to the Colbert, Oklahoma, serving the communities of Sherman and Denison, Texas. This photograph shows the end signage for the US route, as it prepares to transition into Interstate 45 southbound. Photo taken by Justin Cozart (12/02).
Perspective from Interstate 35E south
This upcoming exits sign indicates that Interstate 35E southbound is within one mile of the Woodall Rogers Freeway (unsigned Texas Spur 366). The freeway is a short connector between Interstate 35E and the northern terminus of hidden Interstate 345 and U.S. 75. The highway may continue westward if the proposed Trinity River Tollway is ever constructed. Photo taken by Eric Stuve (12/16/02).
Interstate 35E southbound at Exit 429B/Continental Avenue/Commerce Street West in Dallas. This is about one half mile north of Texas Spur 366. The Woodall Rogers Freeway provides an alternate route to Interstate 45 in lieu of Interstate 35E to Interstate 30 through the Mixmaster Interchange. Photo taken by Eric Stuve (12/16/02).
The predecessor to the overhead assembly above was this full sign bridge. The Exit 429B ramp to downtown Dallas actually parallels Interstate 35E southbound for one half mile, allowing departing traffic to depart the freeway before the Mixmaster Interchange which begins just south of Commerce Street. Exit 429A to Texas Spur 366 utilizes the high flyover in the background. Photo taken 01/96.
Ramp to Interstate 30 east from Interstate 35E south that includes signage for the nearby northern terminus of Interstate 45. This is the northern end of the Mixmaster Interchange. Photo taken 01/96.
Perspective from Interstate 30 west
The first sign of the upcoming junction with Interstate 45 south/U.S. 75 and Interstate 345 north. The symmetrical stack interchange is 1.25 miles to the west. Exit 48A meanwhile departs from the right to Carroll Avenue. Photo taken by Chris Patriarca (06/20/03).
Upcoming junctions overhead for Exit 47C/1st Avenue and the Exit 47B junction of Interstate 45/U.S. 75. These types of signs are common in the Dallas-Fort Worth metropolitan area. Photo taken by Chris Patriarca (06/20/03).
Westbound Interstate 30 at the stack interchange between Interstate 45 and U.S. 75/Exit 46B. The downtown Dallas skyline sets the tone for this busy urban junction. To the left Exit 47A for the Central Expressway prepares to depart. Portions of this roadway represent the original Interstate 45 in the city of Dallas. Photo taken by Chris Patriarca (06/20/03).
Departing via Exit 47B ramps to the top level of the stack interchange. This sign bridge diverts traffic to Interstate 45 south and Interstate 345/U.S. 75 northbound. Photo taken by Chris Patriarca (06/20/03).
Perspective from Interstate 30 east
While in the Mixmaster Interchange, Interstate 30 and Interstate 35E briefly parallel one another. This photograph is taken from Interstate 30 eastbound, but shows the Interstate 35E signage and exit for Lamar Street. A ramp ahead allows Interstate 35E traffic to slip onto Interstate 30 east. Photo taken by Eric Stuve (12/16/02).
Still within the Mixmaster Interchange, Interstate 30 eastbound sees Exit 46 signage for Interstate 45/U.S. 75. The joint termini occurs in 1.25 miles. The roadway to the right is that of Interstate 35E again. Photo taken by Eric Stuve (12/16/02).
Now within one half mile of Interstate 45/Exit 46, Interstate 30 eastbound prepares to accept merging traffic from Interstate 35E. Just to the west of the northern terminus interchange of Interstate 45 is an interchange with the Central Expressway. This roadway is significant in that it represents the original routing of U.S. 75 before it was truncated to Interstate 30. Photo taken by Eric Stuve (12/16/02).
Interstate 30 Exit 46 ramp departure for the beginnings of Interstate 45 south and U.S. 75/Hidden Interstate 345 north. For traffic continuing eastward along Interstate 30, the beginning of another U.S. highway is encountered in eight miles. That is the eastbound beginning of U.S. 80. Photo taken by Eric Stuve (12/16/02).
The Exit 46 ramp split from Interstate 30 eastbound. Interstate 45 ends 285 miles south of here in Galveston, while U.S. 75 does not conclude until it reaches the U.S./Canada border near Noyes, Minnesota. Interstate 345 northbound ends in 1.26 miles at hidden Texas Spur 366/Woodall Rogers Freeway. Photo taken by Eric Stuve (12/16/02).


  1. Michael R. Wilson, email: "I-45/I-345/US-75 in Dallas" August 11, 2003
  2. "From Anywhere to Everywhere: The Development of the Interstate Highway System in Texas." by Penny Beaumont, Rhonda Brinkmann, David Ellis, Chris Pourteau, and Brandon V. Webb, Texas Transportation Institute, page 29 and 34.
  3. Celebrating the 50th Anniversary of the Eisenhower Interstate Highway System: Previous Interstate Facts of the Day by the Federal Highway Administration (FHWA).
  4. Chapter 6 Excerpt: US 175, S.M. Wright and C.F. Hawn Freeways, Dallas-Fort Worth Freeways, 2014 ebook.

Page Updated June 30, 2015.

privacy policy