Kansas City Union Station (station code: KCY) is a union station that opened in 1914, serving Kansas City, Missouri, and the surrounding metropolitan area. It replaced a small Union Depot built in 1878. Union Station served a peak annual traffic of more than 670,000 passengers in 1945 at the end of World War II, but traffic quickly declined in the 1950s, and the station was closed in 1985.

In 1996, a public–private partnership undertook a $250 million restoration, funded in part by a sales tax levied in Kansas and Missouri counties of the Kansas City metropolitan area. By 1999, the station had reopened as a suite of attractions, including museums. In 2002, train service returned when Amtrak began public transportation services, and the station became Missouri's second-busiest train station. The refurbished station has theaters, ongoing museum exhibits, and attractions such as Science City, the Irish Museum and Cultural Center, and the Todd Bolender Center for Dance and Creativity. Since 2016, it has been a stop for the KC Streetcar.

On April 8, 1878, Union Depot opened on a narrow triangle of land in Kansas City, Missouri, between Union Avenue and the railroad tracks of the Hannibal and St. Joseph Railroad in what became West Bottoms. Nicknamed the "Jackson County Insane Asylum" by those who thought it was too large. It was the second union station in the country, after the Indianapolis Union Station. Union Depot's architecture was a hybrid of Second Empire and Gothic Revival. The lead architect was Asa Beebe Cross, who "adorned the exterior of the building with intricate towers of varying heights, arched windows framed in stone and rows of dormers projecting from the steeply pitched mansard roof". It had a clock tower above the main entrance that was 125 feet (38 m) in height. By the 20th century, over 180 trains were passing daily through the station, serving a city population that had tripled. In 1903, the lack of room for expansion and a major flood led the city and the railroads to decide a new station was required.

The decision to build a new station was spearheaded by the Kansas City Terminal Railway, a switching and terminal railroad that was a joint operation of several railroads: Alton; Atchison, Topeka and Santa Fe; Chicago, Burlington and Quincy; Chicago Great Western; Chicago, Milwaukee, St. Paul and Pacific; Chicago, Rock Island and Pacific; Kansas City Southern; Missouri-Kansas-Texas; Missouri Pacific; St. Louis-San Francisco; Union Pacific; and Wabash.

The new location was at a valley at 25th Street and Grand Avenue used by the Kansas City Belt Railway. It was south of the central business district, above and away from the floodplain. Architect Jarvis Hunt was a proponent of the City Beautiful movement. The Beaux-Arts architecture design was a main hall for ticketing, and a perpendicular hall extending out above the tracks for passenger waiting. The building encompassed 850,000 square feet (79,000 m) and the ceiling in the Grand Hall is 95 feet (29 m) high. There are three chandeliers weighing 3,500 pounds (1600 kg) each, and the Grand Hall clock face is 6 feet (1.8 m) in diameter. The building's scale reflects Kansas City's central location as a hub for both passenger and freight rail traffic.

The station opened on October 30, 1914, as the third-largest train station in the country.

The Kansas City massacre occurred on June 17, 1933, in front of Union Station, while captured fugitive Frank Nash was to be delivered to prison via train. Four lawmen (including FBI) were murdered by the Kansas City crime family with Tompson submachine guns in an attempt to free Nash, who was also killed in the gun battle. The massacre highlighted the lawlessness of Kansas City under the Pendergast Machine and resulted in the arming of all FBI agents.

In 1945, annual passenger traffic peaked at 678,363. The demand for a large train station declined in the 1950s. In 1973, it had 32,842 passengers, all passenger train service was now run by Amtrak, and the building was deteriorating. Kansas City government wanted to preserve and redevelop the building, and, in 1974, made a development deal with Canadian redeveloper Trizec Corporation. Between 1979 and 1986, Trizec constructed two office buildings on surrounding property, but did not redevelop the station. The deteriorating station closed in 1983, except a "bubble" inside the main hall housing Amtrak's operations until 1985, when all passenger operations were moved to a smaller "Amshack" facility adjacent to the old station. In 1988, the city sued Trizec for the failure to develop the station and settled in 1994. For most of this period, the building continued to decay.

In 1996, residents in five counties throughout the Kansas City metropolitan area in both Kansas and Missouri approved the so-called "bistate tax", a 1/8 of a cent sales tax, part of which helped to fund just under half of the $250 million restoration of Union Station. Renovation began in 1997 and was completed in 1999. The remaining money was raised through private donations and federal funding. The renovations enabled Amtrak to move its operations back inside the main building in 2002.

Union Station receives no public funding. Operating costs are funded by general admission and theater ticketing, grants, corporate and private donations, commercial space leases, and facility rental. Union Station Kansas City, Inc., a nonprofit 501(c)(3) organization, manages Union Station and had previously managed the Kansas City Museum. Union Station hosts Science City (opened in 1999), a family-friendly interactive science center with more than 50 hands-on exhibits; the H&R Block City Stage Theater, a live-action venue with productions for all ages; the Regnier Extreme Screen, the largest movie screen in the region at five and half stories tall; two restaurants, including Pierponts, an upscale steak and seafood restaurant, and Harvey's; many shops; the Gottlieb Planetarium, the largest planetarium in the area; and various temporary museum exhibits including Dead Sea Scrolls in 2007, Bodies Revealed in 2008, Dialog in the Dark in 2009, Dinosaurs Unearthed in 2010 and Diana, A Celebration focusing upon Princess Diana in 2011. The Irish Museum and Cultural Center has been located in the station since March 17, 2007.

The old Union Station Powerhouse building was renovated by the Kansas City Ballet. It is the ballet's new home and has been named the Todd Bolender Center for Dance and Creativity since August 2011.

In April 2015 and 2017, the reality TV show American Ninja Warrior was filmed at Union Station.

The 2023 NFL draft was held in front of, and partially inside, Union Station in April 2023.

On February 14, 2024, another mass shooting occurred in front of Union Station immediately after the Super Bowl LVIII victory parade and rally honoring the Kansas City Chiefs. One person was killed and 22 others were injured.

The station is served by four Amtrak trains daily. The Missouri River Runner has round trip service to Gateway Transportation Center in St. Louis. The Southwest Chief departs for Chicago Union Station in the morning and for Los Angeles Union Station late evening.

Of the twelve Missouri stations served by Amtrak, Kansas City was the second busiest in the 2015 fiscal year, boarding or disembarking an average 421 passengers daily.

• List of Amtrak stations
• Pencoyd Railroad Bridge (Kansas City, Missouri)

• Official website

• Kansas City, MO – Amtrak
• Kansas City, MO – Station history at Great American Stations (Amtrak)
• 360KC.com, Union Station, 360° visual Internet tours Archived October 26, 2020, at the Wayback Machine