| Bridge Name: | Monitor–Merrimac Memorial Bridge–Tunnel |
| Locale: | Suffolk to Newport News, Virginia |
| Crosses: | Hampton Roads |
| Maint: | Virginia Department of Transportation |
| Clearance: | 14feet |
| Lanes: | 4 total: 2 northbound lanes, 2 southbound lanes |
| Design: | Composite: low-level trestle, double-tube tunnel, artificial islands |
| Length: | 4.6miles |
| Mapframe-Zoom: | 10 |
The Monitor–Merrimac Memorial Bridge–Tunnel (MMMBT) is the 4.6-longNaN-long Hampton Roads crossing for Interstate 664 (I-664) in the southeastern portion of Virginia in the United States. It is a four-lane bridge–tunnel composed of bridges, trestles, artificial islands, and tunnels under a portion of the Hampton Roads harbor where the mouths of the James, Nansemond, and Elizabeth rivers come together.
It connects the independent cities of Newport News on the Virginia Peninsula and Suffolk in South Hampton Roads and is part of the Hampton Roads Beltway, a circumferential Interstate Highway which links the seven largest cities of Hampton Roads.
The MMMBT, completed in 1992, provided a third major vehicle crossing of the Hampton Roads harbor area, supplementing the Hampton Roads Bridge–Tunnel which carries I-64 between the independent cities of Hampton and Norfolk (1957), and the James River Bridge connecting the independent city of Newport News and Isle of Wight County in the South Hampton Roads region (1928).
The MMMBT cost $400 million to build, and it includes a four-lane tunnel that is 4800feet long, two artificial portal islands, and 3.2miles of twin trestle.
The MMMBT is named for the two ironclad warships which engaged in the famous Battle of Hampton Roads on March 8–9, 1862, during the US Civil War. The battle took place between and . The latter ship had been rebuilt from the wreck of . The site of the battle was within 1miles of the bridge–tunnel structure named by the Commonwealth of Virginia as a memorial.