King Street Station is a train station in Seattle, Washington, United States. It is served by Amtrak's Cascades, Coast Starlight, and Empire Builder, as well as Sounder commuter trains run by Sound Transit. The station also anchors a major transit hub, which includes Link light rail at International District/Chinatown station and Seattle Streetcar service. It is located at the south end of Downtown Seattle in the Pioneer Square neighborhood, near the intersection of South Jackson Street and 4th Avenue South, and has four major entrances. It is the 15th-busiest station on the Amtrak system, serving as the hub for the Pacific Northwest region.

Opened on May 10, 1906, it served as a union station for the Great Northern Railway and the Northern Pacific Railway, both owned by James J. Hill. The station was designed by Reed and Stem and incorporated elements from various architectural styles, including a prominent clocktower inspired by St. Mark's Campanile in Venice. A second city terminal, Union Station, was built one block to the east and opened in 1911. As passenger train service declined in the mid-20th century, King Street Station fell into disrepair and was renovated several times to conceal interior elements in the name of modernization. It was selected as Amtrak's sole Seattle station in 1971 and was listed on the National Register of Historic Places two years later. Commuter rail service began in 2000 from a new platform and pedestrian bridge at South Weller Street. King Street Station was acquired by Seattle's city government in 2008 and renovated in 2013 at a cost of $55 million, restoring its original fixtures.

The current station consists of ten tracks and four platforms, including one that is used by Sounder commuter trains and connected via a pedestrian bridge on South Weller Street. The remaining platforms, accessed from the station's waiting room, are used for Amtrak services and special event trains.

Built between 1904 and 1906 by the Great Northern Railway and Northern Pacific Railway, the station replaced an antiquated station on Railroad Avenue, today's Alaskan Way. Designed by the firm of Reed and Stem of St. Paul, Minnesota, who acted as associate architects for the design of Grand Central Terminal in New York City, the station was part of a larger project to bypass the congested railyards along the waterfront by diverting mainline traffic into a planned tunnel under downtown. The depot's 242-foot (74 m) tower was modeled after the recently collapsed Campanile di San Marco in Venice, Italy, making it the tallest building in Seattle at the time of its construction. This tower contained four huge mechanical clock faces built by E. Howard & Co. of Boston, Massachusetts, offering the time to each of the four cardinal directions. At the time of installation it was said to be the second largest timepiece on the Pacific Coast, second only to the Ferry Building in San Francisco, California. Later, this tower also served as a microwave tower for the Burlington Northern Railroad, the successor of both the Great Northern and Northern Pacific railways, whose offices occupied the second and third floors of the station. King Street Station was Seattle's primary train terminal until the construction of the adjacent Oregon & Washington Depot, later named Union Station, in 1911; the 1912 Baist's Real Estate Atlas of Seattle still refers to King Street Station as "Union Passenger Depot".

After the end of World War II, as passenger rail travel began to decline across the United States, steps were taken to gradually modernize King Street Station. The ticket counters, once located directly to the east of the compass room, were expanded outward into the waiting room. In the late 1940s a set of "electric stairs" and a new side entrance to the second floor railroad offices were built over the open stairwell to Jackson Street, narrowing them by half. Over the next two decades, as train ridership and the station's number of employees dwindled, the station was further remodeled to reduce maintenance and heating costs. In the late 1950s the station's original high-back benches, made of yellow oak, were replaced by modern chrome and plastic seats. The final blow to the station's character occurred in late 1967 when, under the direction of Northern Pacific architect A.C. Cayou, a new drop ceiling of plastic and metal was installed in the waiting room ten feet below the original, concealing the hand-carved coffered ceiling to just below the balcony and second level arcade. Hundreds of holes had to be punched through the plaster to attach the ceiling's support wires to the steel frame of the building. The new ceiling held new fluorescent lights and heat lamps, replacing the original brass chandeliers and sconces. Below the new ceiling, plaster reliefs, marble panels, glass tile mosaics and other original fixtures were sheared from the walls and replaced with sheet rock and Formica paneling. The dedicated women's waiting room at the southwest corner of the building was converted into employee offices; its own architectural details suffering the same damage. The only original remaining features left visible in the main waiting area were the terrazzo tile floor and the clock on the west wall above the restrooms.

Despite the attempted modernization, the station continued to deteriorate. Following the creation of Amtrak in 1971 to take over the money-losing passenger service from the railroad companies, hundreds of routes were eliminated and service across the country was cut in half. Amtrak consolidated all of its Seattle service at King Street Station, resulting in the closure of Union Station, which formerly served Union Pacific (the Milwaukee Road had moved out a decade earlier). To further cut costs the station's restaurant, lunch counter, and gift shop were immediately closed and vending machines installed. Eventually even the escalators stopped running and without the funds or passenger volume to justify repairing them, were permanently walled off.

Today, the station has been fully restored and is part of a group of transportation facilities in the southern portion of Downtown Seattle. King Street Station is located a block away from the International District/Chinatown station of the Downtown Seattle Transit Tunnel serving the Link Light Rail 1 Line. Many King County Metro and Sound Transit Express bus routes serve the area, and the First Hill line of the Seattle Streetcar network stops nearby. After many years, the original upper entrance off of Jackson Street has been reopened. The station entrance located on the first floor off King Street now also has a passenger drop-off loop for vehicles, instead of a small parking lot.

Plans to restore the entire building to its former prominence, including cosmetic renovations to both the station interior and exterior, began in 2003. As part of these renovations the Compass Room and restrooms were refurbished, and the exterior awnings were replaced. New mahogany entry doors and wood framed windows were installed in the waiting room and Compass Room. New brass door hardware and reproduction period light fixtures and plaster decorative work were included to reproduce the former character of the station's interior.