WUSA (channel 9) is a television station in Washington, D.C., affiliated with CBS. It is the flagship property of Tegna Inc., which is based in suburban McLean, Virginia. WUSA's studios and transmitter are at Broadcast House on Wisconsin Avenue in northwest Washington's Tenleytown neighborhood. Among CBS affiliates not owned and operated by the network, WUSA is the second-largest by market size (after Tegna's KHOU in Houston).

The station's signal is relayed on a low-power digital translator station, W27EI-D, in Moorefield, West Virginia (which is owned by Valley TV Cooperative). It has a channel-sharing agreement with Silver Spring, Maryland–licensed WJAL (channel 68, owned by Entravision Communications).

The station first went on the air on January 11, 1949, as WOIC. It began full-time operations on January 16. The fourth-oldest station in the nation's capital, channel 9 was originally owned by the Bamberger Broadcasting Service, a subsidiary of R. H. Macy and Company. Bamberger also owned WOR-AM-FM in New York City, and was working to put WOR-TV (channel 9, now WWOR-TV in Secaucus, New Jersey) on the air at the same time. Nine days later, WOIC broadcast the first televised American presidential inaugural address, given by President Harry S. Truman. WOIC picked up the CBS affiliation upon signing on, replacing WMAL-TV (channel 7, now WJLA-TV) as the network's Washington outlet. WOIC/WTOP/WUSA has been a CBS affiliate since its inception, and is currently the network's longest-tenured affiliate. However, WOR was a shareholder in the Mutual Radio Network, which had plans to enter television. Plans for the proposed Mutual-branded network advanced far enough that, at the annual meeting of Mutual stockholders in April 1950, network president Frank White made an official announcement of the planned creation of a limited five-station Mutual network (Boston, New York, Washington, D.C., Chicago, & Los Angeles). At that same time Mutual radio station KQV in Pittsburgh, which was engaged in an ultimately unsuccessful attempt to get a television license, was reportedly hoping for their station to be a Mutual television affiliate. "Mutual Television Network" ended up being the decided-on branding for the Mutual-branded network. However, the 5-station Mutual network failed in short time. Also, at the start of 1950, Bamberger Broadcasting changed its name to General Teleradio.

In June 1950, a joint venture of CBS and The Washington Post purchased WOIC from Bamberger/Macy's for $1.4 million. The new owners, WTOP Incorporated (the Post owned 55%, with CBS holding the remaining 45% stake), changed the station's call sign to WTOP-TV, after its new sister station WTOP radio (then at 1500 AM). In July 1950, WTOP-TV became the first television station in Washington authorized to broadcast color television in the 405-line field sequential color standard, which was incompatible with the black-and-white 525-line NTSC standard. Color broadcasts continued for nearly 30 months, when regulatory and commercial pressures forced the FCC to rescind its original color standard and begin the process of adopting the 525-line NTSC-3 standard, developed by RCA to be backwards compatible with the existing black-and-white televisions.^{[citation needed]}

In 1954, the WTOP stations moved into a new facility, known as "Broadcast House", at 40th and Brandywine Streets NW in Washington. The building was the first in the country designed as a unified radio and television facility. Its name was in honor of Broadcasting House, home of the BBC in London. The building was well known to WTOP's president, since he had spent much of World War II assigned to the BBC. Previous to the move to Broadcast House, the radio stations operated out of the Earle Building (now the Warner Building, home of the Warner Theatre), and WTOP-TV had operated out of the small WOIC studios at the same location. When Broadcast House was completed and the new television studios were inaugurated, the old studio became the garage for Broadcast House and the old master control room became both the master control and transmitter room for channel 9, since Broadcast House had been built around the station's original, four-sided tower. The building with the tower remains in the middle at the same location, although it is now an office building and retail store front.

The WTOP-TV tower was known in Washington for two things. First, at Christmas time, the tower was strung with Christmas lights and glowed brightly on top of Mount Reno, the tallest point in the District of Columbia. Second, the tower tended to sway much more than three-sided towers. In a strong wind, the tower could be seen swaying back-and-forth, and during the winter ice from the tower fell quite often on the streets below.

In October 1954, CBS sold its share of WTOP Inc. to the Washington Post to comply with the FCC's new seven-station-per-group ownership rule. CBS's partial ownership of WTOP radio, KQV radio in Pittsburgh and WCCO radio in Minneapolis exceeded the FCC's limit for AM radio stations. CBS opted to sell its share of WTOP, which it had purchased in whole in 1932 before selling controlling interest to the Post in 1949.

After the sale closed, the Post merged the WTOP stations with its other broadcast property, WMBR-AM-TV in Jacksonville, Florida, and changed the name of the licensee from "WTOP Inc." to "Post Stations, Inc." WMBR radio was sold off in 1958, and WMBR-TV became WJXT. The Post renamed its broadcasting group "Post-Newsweek Stations" in 1961 after the Post bought Newsweek magazine. Post-Newsweek acquired its third television station, WLBW-TV (now WPLG) in Miami in 1970 and in 1974 added WTIC-TV (now WFSB) in Hartford, Connecticut, to the group. In 1972, WTOP-TV joined with the Evening Star Broadcasting Company (owned by the Post's rival, the now-defunct Washington Star and licensee of WMAL-TV) to build the Joint Tower, a 1,040-foot (320 m), three-sided tower across the alley from Broadcast House at 4010 Chesapeake Street NW. Transmission lines were extended from Broadcast House's transmitter area to the new tower for both WTOP-TV and WHUR-FM (the former WTOP-FM, which had been donated by Post-Newsweek to Howard University in 1971). The old tower continued to serve as the backup antenna for channel 9 until the station sold Broadcast House in 1996.