A section of Northeast Expressway, between Eastern and Lincoln Boulevards, was the first four-lane roadway to open in Oklahoma. That roadway, opened in October 1950, was later designated as part of Interstate 440.2 I-440 formed the northern third of the Oklahoma City belt line to Interstate 35 near Lake Aluma. I-240 was designated along the southern loop, from I-40 west of Downtown Oklahoma City south and east back to I-40 beyond Tinker Air Force Base.
Interstates 240 and 440 encircling Oklahoma City – 1971 Official Oklahoma Highway Map. I-240 west from I-35 is the Southwest Expressway, while the freeway east to I-40 is the Southeast Expressway.
Approved by AASHTO on June 17, 1975, I-440 was renumbered as Interstate 240, giving the entire loop a single designation. Exit numbers assigned to the freeway initially used the mileage for I-40.
I-40 east approaching the exchange with then-Interstate 240 in 1978. Photo taken by Bill Manning.
Further changes for Interstate 240 were made, with Interstate 44 overtaking both the original I-440 section, and the north-south leg of I-240 as part of its extension from the Turner Turnpike near Edmond south to Lawton and Wichita Falls, Texas. AASHTO approved the designation changes on June 28, 1982.
I-44 leading south from I-240 to the H.E. Bailey Turnpike north end at Newcastle was designated as U.S. 62 from 1965 to 1982. I-240 from U.S. 62 to U.S. 66 opened on March 23, 1976. From 1978 to 1980, U.S. 66 was detoured along Portland Avenue north to NW and NE 63rd Streets east and Kelley Avenue south while Interstate 240 was constructed.3