Interstate 695 (I-695) is a 51.46-mile-long (82.82 km) auxiliary Interstate Highway that constitutes a partial beltway extending around Baltimore, Maryland, United States. I-695 is officially designated the McKeldin Beltway but is colloquially referred to as either the Baltimore Beltway or 695. The route is an auxiliary route of I-95, intersecting that route southwest of Baltimore near Arbutus and northeast of the city near White Marsh. It also intersects other major roads radiating from the Baltimore area, including I-97 near Glen Burnie, the Baltimore–Washington Parkway (B–W Parkway; MD 295) near Linthicum, I-70 near Woodlawn, I-795 near Pikesville, and I-83 in the Timonium area.

Originally, a 19.37-mile (31.17 km) portion of the Baltimore Beltway between I-95 northeast of Baltimore and I-97 south of Baltimore was officially Maryland Route 695 (MD 695) and was not part of the Interstate Highway System, but is still signed as I-695. The Francis Scott Key Bridge that crossed over the Patapsco River was included in this section of the route before the bridge's collapse on March 26, 2024. The bridge and its approaches were maintained by the Maryland Transportation Authority (MDTA), while the remainder of the Baltimore Beltway is maintained by the Maryland State Highway Administration (MDSHA). The American Association of State Highway and Transportation Officials approved the redesignation of MD 695 as I-695 on April 29, 2024.

The Baltimore Beltway was first planned in 1949 by Baltimore County; the state eventually took over the project, becoming part of the Interstate Highway System planned in 1956. The length of the route from MD 2 south of Baltimore clockwise to U.S. Route 40 (US 40) northeast of the city opened in stages from 1955 to 1962, providing an Interstate bypass of Baltimore. It was the first beltway in the US to be built as part of the Interstate Highway System. Plans were made to finish the remainder of the route, with a diversion to the Windlass and Patapsco freeways, opened in 1973, following the cancelation of a more outer route that was to partly follow what is today MD 702 (Southeast Boulevard).

The Outer Harbor Crossing over the Patapsco River, which was dedicated to Francis Scott Key, who wrote "The Star-Spangled Banner", and its approaches were finished in 1977, completing the route around Baltimore. The approaches to the bridge were originally two lanes to accommodate a tunnel that was initially proposed to run under the river; in subsequent years, they were upgraded to a four-lane configuration compliant with Interstate Highway standards, allowing for this portion of the route to be signed as I-695 rather than MD 695. There are plans for I-695 that include high-occupancy toll (HOT) lanes to ease traffic. In addition, the northeastern interchange with I-95 was reconstructed in 2014 to accommodate express toll lanes that were added to I-95, and construction took place in 2016 to remove I-695's carriageway crossovers here.

Starting at the zero milepost in Baltimore, I-695, which is maintained by the MDTA, is four lanes wide. The route passes over Curtis Creek on a pair of drawbridges here, which have 58 feet (18 m) of vertical navigational clearance and provide access for tall ships to a US Coast Guard base further upstream. Continuing west through industrial areas into Anne Arundel County, the route encounters the northern terminus of MD 10 (Arundel Expressway) at a directional interchange, where maintenance switches to MDSHA. The interchange includes access to the next interchange, with MD 2 (Ritchie Highway), a major north–south route between Baltimore and the southern suburbs, in Glen Burnie. This interchange has access to northbound MD 2 in both directions and from northbound MD 2 to the westbound direction. Beyond MD 2, I-695 encounters I-895B, a short connector to I-895 (Harbor Tunnel Thruway); this interchange provides access to southbound MD 2 from both directions and to the eastbound direction from southbound MD 2. Immediately past this interchange, I-695 comes to an interchange with the northern terminus of I-97, which terminates on the beltway.

The route continues west as a six-lane freeway, heading west into residential areas of Linthicum. It interchanges with MD 648 (Baltimore Annapolis Boulevard), where 132,330 vehicles travel I-695 every day, before turning northwest and intersecting MD 170 (Camp Meade Road) and passing over the Maryland Transit Administration (MTA)'s Baltimore Light RailLink. The route encounters the B–W Parkway (MD 295) at a cloverleaf interchange where the route's signage changes from east–west to north–south at this interchange. It turns more to the north from here and heads into commercial areas, interchanging with MD 168 (Nursery Road) and Hammonds Ferry Road. Past this interchange, the route crosses the Patapsco River into Baltimore County and soon encounters a partial interchange with I-895 (Harbor Tunnel Thruway) with access only from the southbound direction of I-695 to I-895 northbound and from I-895 southbound to the northbound direction of I-695. Past this interchange, I-695 heads north, interchanging with Hollins Ferry Road in Lansdowne before passing under CSX Transportation's Baltimore Terminal Subdivision and coming to an interchange with US 1 Alternate (US 1 Alt.; Washington Boulevard) in Arbutus. A short distance later, I-695 comes to a semi-directional interchange with I-95.

I-695 widens to nine lanes past interchange with I-95, with five lanes in the southbound direction and four in the northbound direction. Running northwest, it crosses over Amtrak's Northeast Corridor and comes to a partial interchange with US 1 (Southwestern Boulevard), with a southbound exit and northbound entrance. From here, it continues northwest through residential areas of Catonsville to an interchange with MD 372 (Wilkens Avenue). Narrowing to eight lanes total, with four lanes in each direction, beyond MD 372, the route continues through suburban neighborhoods before coming to an interchange with MD 144 (Frederick Road). At this point, I-695 narrows to seven lanes, with three southbound and four northbound lanes. It continues north and interchanges with Edmondson Avenue before turning northwest and intersecting US 40 (Baltimore National Pike) near the defunct Westview Mall, now a big-box complex. Beyond US 40, I-695 continues north through residential areas, narrowing to six lanes, with three lanes in each direction, before coming to a four-level stack interchange with I-70/MD 570 in Woodlawn.

The Baltimore Beltway narrows from seven to six lanes within the interchange, which contains braided ramps providing access to the next interchange, MD 122 (Security Boulevard), located near Security Square Mall and the headquarters of the Social Security Administration. Continuing north, the road widens to eight lanes again and continues through a mix of suburban homes and business parks in Lochearn. I-695 interchanges with MD 26 (Liberty Road) east of Randallstown and resumes north, narrowing to six lanes. It intersects the southern terminus of I-795 (Northwest Expressway), which serves as a bypass of MD 140 in the Owings Mills area. The MTA's Baltimore Metro SubwayLink line to Owings Mills passes under I-695 within the interchange and runs in the median of I-795 as far as that town. At the I-795 interchange, the signage of route changes from north–south to east–west.