State Route 7 is a north–south state highway in the southern and eastern portions of the U.S. state of Ohio. At just over 292 miles (470 km) in length, it is the longest state route in Ohio. Its southern terminus is an interchange with U.S. Route 52 just west of Chesapeake. Its northern terminus also serves as the eastern terminus of State Route 531 in Conneaut. The path of State Route 7 stays within five miles (8 km) of the Ohio River (Ohio's border with West Virginia) for the southern portion, with the river being visible from much of the route. The road also remains within ten miles (16 km) of the Pennsylvania state line for the northern portion.

The Chesapeake bypass was first proposed in 1953.

In 1961, the U.S. Route 52 expressway opened from Chesapeake westward towards Sheridan. The original eastern terminus of the four-lane divided highway was at the current Chesapeake northbound-only exit ramp east of Tallow Ridge Road . U.S. Route 52 originally crossed at the present-day Robert C. Byrd Bridge that connects Chesapeake to Huntington, West Virginia. In 1979, the U.S. Route 52 designation moved to the Nick Joe Rahall II Bridge as tolls on that span were removed that year; the segment east of the Rahall Bridge to the Chesapeake interchange was renumbered to State Route 7.

Ten years later, the four-lane expressway was extended eastward to an incomplete trumpet interchange just east of Big Branch Road . A four-lane connector route from the partially complete interchange to the foot of the Robert C. Byrd Bridge at State Route 527 was completed. At the same time, the two-lane Chesapeake interchange ramp just east of Tallow Ridge Road was converted to a northbound-only exit ramp. The abrupt terminus at Chesapeake was envisioned to connect to Proctorville.

On May 31, 2002, ground was broken for Phase 1-A of the Proctorville bypass. Phase 1-A entailed a two-lane connector road from the East Huntington Bridge to Irene Road, with the original loop ramp from the bridge to State Route 7 being modified into an access road. Phase 1-B was designated from Irene Road to State Route 7 near Fairland East Elementary in Rome. Phase 2 was envisioned from Irene Road west to Chesapeake. The total cost was originally estimated to be at $165 million.

On April 27, 2003, Phase 1-A of the Proctorville bypass opened to traffic. The $6.5 million, one-mile (1.6 km) section of three-lane roadway was opened from the foot of the East Huntington Bridge to Irene Road and signed as State Route 607.

On June 3, 2003, bids were opened for Phase 1-B from Irene Road to State Route 7 near Fairland East Elementary. The projected cost of the 4.5-mile (7.2 km) segment was originally $27 million, however, when the bids were let, the cost had decreased to $24.3 million. The lowest bid, which was also accepted, came in at $22.1 million. The road was designed as a two-lane limited-access facility on a four-lane right-of-way. Construction began on August 4, with an original estimated completion date of June 30, 2005.

An unusual amount of rain, blamed on two hurricanes, caused major delays. More than one-dozen major slips along Phase 1-B required an additional $30 million in repairs and the purchase of additional land for highwall excavations. Another change was the design of the roadway; originally projected to be widened in the future when higher traffic counts warrant the expansion, it was designed on wide right-of-way with no grade separation between the opposing lanes. During the repair of the slips, a terraced roadway was constructed to separate the future southbound lanes from the northbound by a highwall when the roadway is expanded to four lanes.

Other cost overruns had pushed the cost of construction to $62 million total, which included Phases 1-A and 1-B, up from the original estimates of $32 million. The primary cause was rapidly increasing land values and "unchecked zoning" along the project's projected right-of-way along with geo-technical problems with rocky soil. Property values along the projected route, for instance, increased 91.5% from 1992 to 2001 alone.

In October 2006, a small 1/2-mile segment of the Phase 1-B bypass opened to traffic between the State Route 607 and Irene Road intersection to State Route 775. The remainder, east to State Route 7 near Fairland East Elementary, opened on December 8, 2006. It includes intersections with State Route 775, Kinley Avenue, and State Route 7. Upon completion, Phases 1-A and 1-B were signed as State Route 7; the bypass from the State Route 775 junction to the loop at the East Huntington Bridge was co-numbered with State Route 775.

Phase 2 of the bypass, from the Chesapeake bypass to Irene Road at Proctorville, has not been funded. Funding which had been previously promised by the Ohio Department of Transportation was later denied. Phase 2 is estimated to cost $76 million to complete. Also due to the construction delays (slips) on the bypass from SR 775 to Fairland East Elementary School (Phase 1-B), the design of Phase 2 may be realigned to prevent slips during construction.

The Pomeroy bypass from Middleport east to U.S. Route 33 was completed in 1968. At the time of completion, the bypass was two lanes but was upgraded to four lanes, divided, in 1976 from State Route 143 to U.S. Route 33 near Rock Springs. The bypass was extended east in 2000 from Rock Springs to a partial diamond interchange with State Route 7 as a four-lane divided expressway. It was initially signed just State Route 7. The diamond interchange was later completed with all connections, and the highway was extended eastward to Ravenswood, West Virginia as U.S. Route 33.

Alternate State Route 7 is a short connecting loop (0.72 miles) that serves as a link from State Route 7, U.S. Route 40, and U.S. Route 250 to Interstate 70 in Bridgeport. Its western (southern) terminus is at State Route 767, and its eastern (northern) terminus is along U.S. Route 40 at its intersection with U.S. Route 250 and the northern terminus of State Route 767. Route 7A begins at the intersections of Howard Street and SR 767, South Lincoln Avenue. Route 7A continues West as Howard Street until it intersects Marion Street. Route 7A then runs North as Marion Street, intersects I-70, and then intersects US 40, Main Street. Route 7A continues East on US 40 until it ends at US 250.

The entire route is in Bridgeport, Belmont County.

Business State Route 7 stretches from 1¾ miles west of Middleport to about 4 miles (6.4 km) east of Pomeroy. This route follows the former alignment of State Route 7 that was replaced by the Pomeroy Bypass, and runs through the downtown areas of Middleport and Pomeroy. It joins with State Route 833 (the former alignment of U.S. Route 33) from a mile west of Pomeroy to 1¾ east of Pomeroy, including a brief concurrency with State Route 124, and then heads northeast to the eastern U.S. Route 33/State Route 7 interchange. This route is not listed at ODOT’s Technical Services Straight Line Diagrams as a state-maintained route.

Route 7T is a 0.36-mile (0.58 km)-long temporary route beginning at US 62 in Youngstown. Route 7T dead ends but it is unclear from the straight line diagrams where Route 7T begins and ends.

List of unused highways in Ohio