Virginia’s underwater tunnels are concentrated in the Hampton Roads region, a sprawling harbor area in the southeastern corner of the state where the James River, Elizabeth River, and Chesapeake Bay converge. This cluster of waterways created a unique engineering challenge: how to move hundreds of thousands of vehicles a day across open water in an area home to the world’s largest naval base and one of the busiest ports on the East Coast. The answer was a network of bridge-tunnels and standalone tunnels unlike anything else in the United States.
Hampton Roads Bridge-Tunnel (I-64)
The Hampton Roads Bridge-Tunnel, commonly called the HRBT, is the most well-known underwater tunnel in Virginia. It carries Interstate 64 across the mouth of Hampton Roads harbor, connecting the cities of Hampton and Newport News on the north side (the Virginia Peninsula) to Norfolk and Virginia Beach on the south side. The crossing spans roughly 3.5 miles of open water, with vehicles descending into tunnels that pass beneath the shipping channel.
The HRBT is currently undergoing a $3.9 billion expansion, the largest highway construction project in Virginia’s history. The project adds twin, two-lane bored tunnels under the harbor alongside the original tubes and widens four-lane segments along a nearly 10-mile corridor of I-64. A massive tunnel boring machine named Mary, brought from Germany for the job, completed her final breakthrough in September 2024. Key milestones for the expansion, including the opening of a second bored tunnel and a new bridge span, are expected in 2025.
Chesapeake Bay Bridge-Tunnel (US 13)
The Chesapeake Bay Bridge-Tunnel is the most dramatic of Virginia’s crossings. It carries US Route 13 across the mouth of the Chesapeake Bay, linking Virginia Beach and the Norfolk metro area to the Eastern Shore, a rural peninsula shared with Maryland and Delaware. The full crossing stretches about 17.6 miles, making it one of the longest bridge-tunnel complexes in the world. Vehicles travel over long trestle bridges, then dip underwater through two tunnel sections that allow Navy vessels and commercial ships to pass overhead through the shipping channels.
A parallel tunnel at Thimble Shoal, one of the two tunnel segments, was constructed to expand capacity. The Federal Highway Administration noted construction began in October 2017 with substantial completion expected by October 2022. This addition converted the Thimble Shoal crossing from two lanes to four, relieving a bottleneck that had long caused backups during summer beach traffic and holiday weekends.
Monitor-Merrimac Memorial Bridge-Tunnel (I-664)
The Monitor-Merrimac Memorial Bridge-Tunnel, often abbreviated MMMBT, carries Interstate 664 across the James River between Newport News and Suffolk/Norfolk. Named after the Civil War ironclad warships that fought nearby, it serves as an alternate route to the HRBT for drivers crossing Hampton Roads. The crossing runs about 4.6 miles and features a tunnel section beneath the river’s shipping channel flanked by bridge spans on either side. It tends to carry less traffic than the HRBT, making it a popular detour when I-64 is backed up.
Downtown and Midtown Tunnels (Elizabeth River)
Two shorter tunnels pass under the Elizabeth River between Norfolk and Portsmouth, a pair of cities that sit directly across the river from each other.
The Downtown Tunnel carries I-264 beneath the river. It originally opened as a single tube, with a second tube added in 1988 when the tunnel was incorporated into the interstate system. The Midtown Tunnel runs on Route 58 about a mile to the south. A parallel 4,500-foot tunnel was built alongside the original Midtown Tunnel to improve traffic flow, along with interchange modifications at both ends. An adjacent highway extension connects Route 58 and Route 164 in Portsmouth to Norfolk.
Unlike the larger bridge-tunnel crossings that span open harbors and bays, these Elizabeth River tunnels are urban connectors. They’re shorter, more heavily used by commuters, and tolled.
Hazardous Materials and Vehicle Restrictions
All four urban tunnels in Hampton Roads restrict what vehicles can carry through them. Poison gas is completely prohibited. Nonflammable gases pass without restriction. Flammable gases, including propane, are allowed only in small, non-bulk containers: 119 gallons or less for liquids, 1,000 pounds of water capacity or less for gases. If you’re towing a camper with a standard propane tank for a grill, you’re generally fine. A large commercial propane delivery truck would not be permitted.
Oversized vehicles and certain truck configurations face additional limits. If you’re driving a tall RV or hauling heavy equipment, check posted clearance heights at each tunnel entrance. The CBBT has different rules from the urban tunnels, so restrictions vary by crossing.
Why Virginia Has So Many Tunnels
Geography is the simple answer. Hampton Roads sits where three major rivers empty into the Chesapeake Bay, creating wide, deep shipping channels that must stay open for Navy aircraft carriers, submarines, and massive container ships. Traditional bridges tall enough to clear these vessels would need to be impossibly long and steep, so engineers combined low-profile bridge trestles with underwater tunnel segments at the channel crossings. The result is a region where driving underwater is a routine part of any commute, and where “which tunnel should I take?” is a daily question for about 1.8 million residents.