Damen is a rapid transit station on the Chicago "L", currently serving the O'Hare branch of its Blue Line. Opened on May 6, 1895, as Robey, it is the oldest station on the Blue Line. The station serves the popular Bucktown and Wicker Park neighborhoods, and is consistently in the top 40 highest-ridership "L" stations. It has two wooden side platforms and a brick station house at street level. The west platform, serving southbound trains, contains a tower that has never been used but is a relic of the station's past. The station is served by three bus routes on Damen, Milwaukee, and North Avenues, which are each descended from streetcar lines on those streets in the early 20th century. The Blue Line has owl service; while the surrounding streetcar lines also had owl service in the early 20th century, the modern bus services do not.

Robey was constructed by the Metropolitan West Side Elevated Railroad to serve its Logan Square and Humboldt Park branches, being the last stop on the Logan Square branch before the Humboldt Park branch diverged from it. The Metropolitan's operations, along with the rest of the "L", were assumed by the private Chicago Rapid Transit Company in 1924 and the public Chicago Transit Authority in 1947. The rail lines that had been constructed by the Metropolitan were significantly altered in the 1950s, a process that entailed the closure of the Humboldt Park branch and the replacement of the Logan Square branch south of Damen with the Milwaukee–Dearborn subway. By 1958, this had created the "West-Northwest Route", which was renamed the Blue Line in 1992. The Logan Square branch, renamed the "Milwaukee branch" during this process, was extended to O'Hare International Airport in 1984, forming the O'Hare branch.

Throughout these changes, the Damen station itself remained remarkably well-preserved, being among other things one of the last stations on the "L" system to retain its historic gooseneck lights. Having contributed to the neighborhood's historical development, the station is a contributing property to the Chicago landmarked Milwaukee Avenue District, although it is not itself landmarked. After suffering a decline in the mid-to-late 20th century, the station and neighborhood were in poor shape by the 1980s, though the station received a renovation for the 100th anniversary of its opening in 1995. The neighborhood and station's popularity increased in the early 21st century, leading to another renovation in 2014. Despite these renovations, the station remains limited in its accessibility for disabled patrons due to its advanced age and the neighborhood's protected status.

Proposals for the construction of an elevated railroad above Milwaukee Avenue dated to at least 1872, although opposition existed from the public due to the feared impact on property values. The Metropolitan West Side Elevated Railroad Company was granted a 50-year franchise by the Chicago City Council on April 7, 1892, and began securing right of way shortly thereafter. The Metropolitan's operations comprised a main line that went west from downtown to Marshfield Junction, where three branches – one northwest to Logan Square, one due west to Garfield Park, and one southwest to Douglas Park – diverged and served various parts of Chicago's west side. A further branch to Humboldt Park proceeded due west from the Logan Square branch just past Robey Street. Unlike the competing South Side and Lake Street Elevateds, the Metropolitan never used steam traction. Although it had originally intended to, and indeed had built much of its structure under the assumption that locomotives would be used, it decided in May 1894 to have electrified tracks instead, making it the first revenue electric elevated railroad in the United States.

The Metropolitan's tracks by the site of the future Robey station were finished by the middle of October 1894, and were given power in April 1895 for test and inspection runs. Public opposition led to this part of the elevated being placed above an alley adjacent to Milwaukee Avenue rather than the avenue itself. The Metropolitan began service at 6 a.m. on Monday, May 6, 1895, between Robey on the Logan Square branch and Canal on the main line. Of the eleven stations opened that day, Robey is the only one still surviving, making it the oldest station on what is now the Blue Line. The Logan Square branch was extended to Logan Square on May 25, and the Humboldt Park branch opened on July 29. Robey Street, on which the station lay and named for politician James Robey, was renamed Damen Avenue in 1927 for Father Arnold Damen, leading to a change in the station's name.

The Metropolitan's lines were originally operated by the West Side Construction Company, which had been responsible for constructing them, and were transferred to the Metropolitan on October 6, 1896. The backers and officers of the two companies were largely identical, however, so this transfer of ownership was nominal. The expenses incurred in constructing the Metropolitan's vast trackage would catch up to the company, which entered receivership in 1897; the similarly-named Metropolitan West Side Elevated Railway Company was organized in January 1899 and assumed operations on February 3 of that year. The new Metropolitan, along with the other companies operating "L" lines in Chicago, became a part of the Chicago Elevated Railways (CER) trust on July 1, 1911. CER acted as a de facto holding company for the "L" – unifying its operations, instituting the same management across the companies, and instituting free transfers between the lines starting in 1913 – but kept the underlying companies intact. This continued until the companies were formally merged into the single Chicago Rapid Transit Company (CRT) in 1924, which assumed operations on January 9; the former Metropolitan was designated the Metropolitan division of the CRT for administrative purposes. Although municipal ownership of transit had been a hotly-contested issue for half a century, the publicly-owned Chicago Transit Authority (CTA) was created only in 1945, assuming operation of the "L" on October 1, 1947.

The CTA instituted major changes on the lines built by the Metropolitan that had been planned since the late 1930s. The Logan Square branch south of Damen was replaced by the Milwaukee–Dearborn subway, which opened on February 25, 1951. Upon the subway's opening, the CTA restricted the Humboldt Park branch to a shuttle service to and from Damen, and closed it altogether on May 5, 1952. Combined with the replacement of the main line and Garfield Park branch with the Congress Line in 1958, this formed a new route called the "West–Northwest Route", which entered service on June 22, 1958. This route was renamed the Blue Line in 1992. Skip-stop, where certain "A" and "B" trains stopped at respective "A" and "B" stations, was instituted with the 1951 opening of the subway; Damen was deemed an "all-stop" station and was thus unaffected by this introduction. The Logan Square branch, referred to by the CTA as the "Milwaukee branch" after the completion of the West–Northwest Route, was extended past Logan Square to Jefferson Park on February 1, 1970. Further extensions were made to River Road in 1983 and finally a station at O'Hare International Airport on September 3, 1984, forming the O'Hare branch.

The Damen station remained remarkably well-preserved throughout the 20th century and the early 21st century. Prominent in this were the station's historic gooseneck lights; alongside Wilson, it was one of the last stations on the "L" to retain such lights. Having been credited with spurring development of the surrounding neighborhood upon its construction, the station was included as a contributing property to the "Milwaukee Avenue District", which was designated a Chicago landmark on April 9, 2008. The station was not itself made a landmark; nevertheless, the CTA has presented the landmarked status of its surroundings, and the station's general historic fabric, as part of the excessive difficulty in making the station accessible for disabled people.