Interstate 195 (I-195) is an Interstate highway in the U.S. state of Maryland. The highway runs 4.71 miles (7.58 km) from Baltimore/Washington International Thurgood Marshall Airport (BWI Airport) in Linthicum north to I-95 in Arbutus, where Metropolitan Boulevard continues north as Maryland Route 166 (MD 166). I-195, which is also known as Metropolitan Boulevard, is the main connection between the airport terminal and highways leading to Baltimore, Washington, and Annapolis, including I-95, MD 295, and I-97. The Interstate highway also has an interchange with MD 170, which forms part of the Airport Loop that provides access to various airport-related services. I-195 also links I-95 with Catonsville and the University of Maryland, Baltimore County (UMBC), via MD 166. The Interstate is a part of the National Highway System for its entire length.

I-195 was constructed in three sections. The first section was a connection between MD 295 and the airport. This segment was built as Maryland Route 46 and completed in 1951 shortly after the opening of the airport, which was originally named Friendship International Airport. The second segment was completed at the opposite end of the highway in the mid-1970s, connecting U.S. Route 1 (US 1) and I-95 with MD 166 and UMBC. The first two segments were connected when the portion between MD 295 and US 1 was constructed in the late 1980s. The whole length of the highway was completed and was marked as I-195 in 1990.

I-195 begins at the entrance to BWI Airport. The eastbound roadway continues southeast into the airport proper, where it features a left exit for the hourly parking garage and then splits into two roadways for arriving and departing flights. After the two roadways—arriving flights on the lower level and departing flights on the upper level—loop between the terminal and the hourly parking garage, the roadways merge. The westbound direction of I-195 heads northwest from the airport after it issues a ramp toward long-term parking and a U-turn toward the terminal. I-195 heads northwest as a four-lane freeway, with a speed limit of 30 miles per hour (48 km/h) between the airport and a partial cloverleaf interchange with MD 170 (Aviation Boulevard), also known as the Airport Loop. The Airport Loop provides access to long-term parking lots, the consolidated rental car facility, hotels, cargo and general aviation facilities, and the BWI Rail Station. The circumferential highway also provides indirect access to I-97 for traffic heading to Annapolis or the Chesapeake Bay Bridge.

I-195's speed limit increases to 60 miles per hour (97 km/h) between the overpass for the BWI Trail and a partial cloverleaf interchange with MD 295 (Baltimore–Washington Parkway), which contains a flyover ramp from southbound MD 295 to southbound I-195. The Interstate parallels the Amtrak Northeast Corridor and MARC's Penn Line before elevating onto a viaduct to cross the railroad tracks and the Patapsco River, where the freeway passes from Anne Arundel County to Baltimore County. I-195 crosses over I-895 (Harbor Tunnel Thruway) with no access before its four-ramp partial cloverleaf interchange with US 1 (Washington Boulevard). The highway continues northwest over CSX's Baltimore Terminal Subdivision and meets I-95 at a partial cloverleaf interchange 2 miles (3.2 km) southwest of the I-95–I-695 junction; the interchange features flyovers from northbound I-95 to northbound I-195 and from southbound I-95 to southbound I-195. The highway officially ends at the northern edge of the interchange. The speed limit drops to 50 miles per hour (80 km/h) as the freeway continues as MD 166 under the Selford Road overpass. The highway has a partial interchange for UMBC Boulevard, which leads to the UMBC campus, before ending next to a park and ride facility at Rolling Road, on which MD 166 continues north toward Catonsville.

Friendship International Airport was constructed between 1947 and 1950 as the new primary airport for Baltimore. To directly connect the airport with Baltimore, an access road was planned to link the new Baltimore–Washington Expressway, later designated MD 295, with the airport terminal. The first portion of the Friendship International Airport Access Road was completed from a full Y interchange at the expressway to an interchange with MD 170 in October 1949 and designated MD 46. The access road was completed from MD 170 to the airport terminal in July 1951, about the same time the expressway was completed between MD 46 and downtown Baltimore. The remainder of what is now I-195 was planned as early as 1969, when the portion of Metropolitan Boulevard north of US 1 was placed under construction. The freeway opened from the US 1 ramps northwest through the I-95 interchange to an intersection with Sulphur Spring Road just south of the modern Selford Road overpass in August 1974. The freeway was extended to its present terminus at Rolling Road and the ramps to UMBC Boulevard were constructed in 1975. Metropolitan Boulevard south of the I-95 interchange was marked as a second segment of MD 46 from when it opened. North of I-95, the freeway was marked as a relocation of MD 166. That segment of MD 46 was renumbered as an extension of MD 166 by 1981.

The missing connection between US 1 and MD 295 resulted in a circuitous path for traffic between I-95 and BWI Airport. In 1974, that route involved exiting I-95 at MD 100, which then served as a connector between the Interstate and US 1. Traffic took US 1 south to MD 176, then took MD 176 east to MD 295 and north to the western end of MD 46. Construction on the missing link, which by then was planned as part of I-195, began in 1987, when the highway's bridges over US 1 and I-895 were constructed. The remainder of the highway from MD 295 to the I-895 overpass was completed, including reconstruction of the interchange with MD 295, and the intermediate section opened in June 1990. The I-195 designation was applied to the highway's present length at the same time, and MD 166 was truncated to its present southern terminus. In 2002, as part of an expansion project at the airport, several new ramps were constructed to access parking lots and facilitate an easier U-turn for motorists leaving the terminal who wish to return to the terminal.