Fort Carroll is an artificial reef located 1609 metres from shore in the Maryland-Virginia Quarries. The site sits at a depth of 15 metres, with an average depth of 9 metres. Divers should expect visibility around 5 metres and mild currents, though conditions can vary. Access is by boat only. The artificial substrate supports a variety of local reef fish and invertebrates. Due to the low visibility and potential for entanglement within the structure, careful buoyancy control is required. Divers must remain aware of active boat traffic overhead and are advised to deploy a surface marker buoy before ascending.

Loch Raven Cliffs is a quarry site in the United States offering depths ranging from 3 to 73 metres. Access is via shore, though the site is primarily suited for advanced divers due to challenging conditions including low visibility of 1 to 3 metres, entanglement risks, and down currents. The water temperature fluctuates between 4C and 28C, with significant thermal stratification occurring during summer months. Divers should be aware of boat traffic and the presence of a thermocline. Parking is available near the site. Snorkelling is not recommended here, as the site receives a rating of 1/5 for that activity.

Merryman's Trail Beach is a freshwater dive site located at the Maryland-Virginia Quarries near Loch Raven Reservoir. This artificial reef site features a sandy shoreline entry point situated just north of the Loch Raven Drive bridge. Divers should be aware of significant thermal stratification, with surface temperatures ranging from 4C to 19C and deeper water remaining consistently cold. Depths at this site extend to 73 metres. Due to the proximity to the main road and potential for boat traffic, divers must exercise caution. The site is suitable for beginners, though conditions vary and visibility can be low.

Sandy Point is a muck diving site located in the Chesapeake Bay, accessible via shore entry. The site is characterised by very limited visibility and moderate currents, requiring intermediate skill levels for safe navigation. Depths are shallow, ranging between 1 and 2 metres. Divers should remain aware of boat traffic and the presence of jellyfish in the water. The site offers facilities including parking, toilets, showers, changing rooms, and a cafe. Diving here is restricted and typically conducted during organised events. Water temperatures fluctuate significantly throughout the year, ranging from 4C in winter to 28C in mid-summer.

Pot Rocks is a freshwater canyon site located within the Maryland-Virginia Quarries. The site is defined by geological formations where the river has carved deep pots or holes into the bedrock. These underwater rock formations create a distinct topography for snorkellers to explore. The site is suitable for advanced snorkellers due to the presence of moderate currents and cold water conditions. Depths at this location range between 1 and 5 metres. Access to the water is via the shore, and parking facilities are available nearby for visitors.

Hobo Beach at York Road Access offers a freshwater snorkeling experience within the Maryland-Virginia Quarries region. The site features a grassy bank entry leading into a deep, slow-moving section of the river. Depths at this location range from 8 to 39 metres. Water temperatures remain consistently cold, between 45 and 50 degrees Fahrenheit, due to the release from the nearby Prettyboy Reservoir. The site is suitable for beginners, though the deep water and cold temperatures require appropriate thermal protection. Facilities at the access point include parking and toilets. Typical sessions last approximately 45 minutes, with mild currents present throughout the area.

Bunker Hill is a deep pool located within the Maryland-Virginia Quarries near Prettyboy Reservoir. This freshwater site features a slower river flow, which allows for observation of the riverbed. Snorkellers can expect mild currents, though the water remains cold year-round, typically ranging between 45-50°F due to reservoir releases. The site is suitable for beginners and offers shore access. While specific sightings are not confirmed, the habitat supports various temperate freshwater fish and invertebrates typical of the region. Facilities at the site include parking and toilets. Due to the consistently low water temperatures, appropriate thermal protection is necessary for all visitors.

Hemlock Gorge is a shallow snorkelling site located below the dam near Prettyboy Reservoir. The area consists of shallow riffles and small pools shaded by hemlock trees. With an average depth of one metre and a maximum depth of two metres, it is suitable for beginners. Entry is via the shore. Conditions vary, with visibility typically ranging between one and four metres and moderate currents present. Snorkellers should be aware of potential entanglement hazards in the water. A typical session lasts approximately 30 minutes.