Route

Eastern Seaboard

North-to-south traverse along the eastern continental margin. The longest route in the collection by distance. Passes through formerly dense settlement—vegetation has reclaimed most structures, but road surfaces are partially intact beneath overgrowth. Terrain ranges from northern hardwood forest to subtropical coast. Overhead clearance constraint in the northern section. Tidal marshland navigation required in the southern third. Terminus at a subtropical coast with active antenna infrastructure.

Distance: ~2,100 km
Elevation: 0–480 m
Gain / Loss: +4,200 m / −4,200 m
Min. Clearance: 220 mm
Breakover: 16°
Max. Gradient: 10%
Max. Ford: 700 mm (spring: +250 mm)
Min. Overhead: 3.2 m (km 180–260)
Obstacles: 22 >300 mm / 6 >500 mm
Surface: 55% degraded asphalt, 20% gravel, 25% soil/vegetation

Segments

km 0 — 300

Origin at a maintained structure on a rocky northern coast: stone foundation, timber frame, slate roof, functional condition. A cleared gravel area provides vehicle staging. The track leads south on a former two-lane road through dense northern hardwood—maple, birch, beech. The canopy has closed over the road in many stretches. Tree growth from the road shoulders narrows the passable width. Between km 180 and km 260, overhead clearance is reduced to 3.2 m by low-hanging branches and leaning trunks. Vehicles exceeding this height will require branch removal. The road surface beneath the canopy is in variable condition: intact asphalt where the canopy provides protection from weather, broken and root-heaved where trees have encroached from the edges. Stream crossings are frequent—eleven in this segment, all with bridges or culverts. Eight are functional; three are degraded and require fording. The deepest ford at km 270 is 350 mm, cobble bottom.

Surface: 60% degraded asphalt, 15% gravel, 25% soil
Min. overhead: 3.2 m (km 180–260)
Max. gradient: 8%
Max. ford: 350 mm
Obstacles: 5 >300 mm / 1 >500 mm (tree fall, root heave, bridge debris)

km 300 — 650

Piedmont. The terrain becomes more rolling as the route moves south through the foothills of the eastern mountain chain. Elevation oscillates between 120 and 480 m. Road surface is consistently degraded asphalt with vegetation growing through joints and cracks. Former settlement density increases significantly in this segment. Evidence of former habitation is visible every few kilometers: foundations, wall remnants, road grids partially visible beneath ground cover. A former multi-lane road is traceable from km 380 to km 520—median vegetation has grown to full tree height, but the pavement on either side remains partially passable. Bridges in this segment are a mix of intact concrete and degraded steel. All major river crossings have bridges; condition should be assessed individually before crossing. Refer to bridge assessment procedures. The river crossing at km 560 is the largest in this segment: a four-span concrete beam bridge, structurally intact, deck surface with some spalling.

Surface: 65% degraded asphalt, 15% gravel, 20% soil/vegetation
Max. gradient: 10%
Max. ford: 500 mm (at bridge bypass points)
Obstacles: 6 >300 mm / 2 >500 mm (collapsed infrastructure, tree fall)

km 650 — 950

Coastal plain transition. Elevation drops below 100 m. The terrain flattens. Tree cover shifts from hardwood to mixed pine and hardwood. Former settlement density remains high but structures are more dispersed. Road surface continues as degraded asphalt. Navigation is straightforward—the former road network is extensive and well-preserved, with multiple parallel routes available. The documented route follows the most direct path with the best-preserved road surface. A large river crossing at km 780 uses a steel truss bridge—single span, approximately 200 m, deck intact, load capacity adequate. At km 870, the terrain becomes noticeably flatter and wetter. Standing water appears in low areas adjacent to the road. Pine gives way to cypress and gum in the lower elevations. Road surface deterioration increases where water damage has undermined the roadbed.

Surface: 55% degraded asphalt, 20% gravel, 25% soil/vegetation
Max. gradient: 5%
Max. ford: 450 mm
Obstacles: 4 >300 mm / 1 >500 mm (roadbed collapse, debris)

km 950 — 1,250

Former dense settlement zone. The evidence of prior habitation is continuous for much of this segment. Road grids, foundation arrays, infrastructure remnants. Vegetation has reclaimed nearly everything to above-canopy height. The road follows a former primary route—wider pavement, median barriers still partially visible. At approximately km 1,100, a large maintained structure complex is visible from the road: brick construction, multiple buildings of varying size, the largest with a distinctive green copper roof patina. A fenced perimeter with cleared grounds—grass mowed or maintained at low height, paths between structures, no vegetation encroachment within the perimeter. Function is not apparent from the road. The complex occupies a slight rise above the surrounding terrain. The route continues past. South of km 1,200, the terrain transitions to coastal lowland. Pine flatwoods, palmetto understory. Road surface becomes more degraded as moisture levels increase.

Surface: 50% degraded asphalt, 20% gravel, 30% soil/vegetation
Max. gradient: 4%
Max. ford: 300 mm
Obstacles: 4 >300 mm / 1 >500 mm (infrastructure debris, roadbed erosion)

km 1,250 — 1,700

Tidal marshland. The route enters a zone where the terrain is at or near sea level. Tidal influence extends well inland through a network of estuaries and marsh channels. Route selection depends on tide tables—several low-lying sections are submerged at high tide. The documented route follows the highest available ground, generally former road embankments and causeways. Three causeway sections are intact but narrow: single vehicle, no shoulder, water on both sides at high tide. One causeway section at km 1,450 has a gap of approximately 30 m where the road surface has collapsed. The ford at this gap is tidal: 200 mm at low tide, 700 mm at high tide. Substrate is firm sand over clay. Beyond the causeway zone, the terrain rises slightly to a series of low barrier ridges. Live oak and saw palmetto. Road surface is sand and compacted shell over degraded asphalt.

Surface: 40% degraded asphalt, 20% sand/shell, 25% gravel, 15% mud
Max. gradient: 3%
Max. ford: 700 mm (tidal, at causeway gap)
Obstacles: 3 >300 mm / 1 >500 mm (causeway gap, road collapse)

km 1,700 — 2,100

Subtropical approach and terminus. The terrain becomes drier and slightly higher as the route moves south along a coastal ridge. Vegetation is subtropical: palm, live oak, sea grape, mangrove at the water line. Road surface is mixed—stretches of intact asphalt alternate with sand and shell. Former settlement evidence is scattered but lighter than the northern segments. At km 1,950, the coastline becomes visible to the east. The final approach follows a former coastal road, partially eroded, with sand encroachment from the beach side. The terminus is at km 2,100: a maintained dock extending into a sheltered harbor, and a concrete-block building approximately 20 m × 10 m, flat roof, with an active antenna array. The antenna array includes a dish approximately 3 m in diameter, several vertical whip antennas, and cabling that is intact and appears maintained. Solar panels on the roof. Equipment hum is audible from the exterior. The dock shows evidence of recent use.

Surface: 45% degraded asphalt, 30% sand/shell, 15% gravel, 10% soil
Max. gradient: 4%
Obstacles: 0 >300 mm

Seasonal variation

Spring: stream crossings in the northern and piedmont segments increase by 150–250 mm. Road surfaces on soil substrates lose bearing capacity during sustained rain. Overhead clearance in the northern canopy segment may decrease slightly as foliage fills out.

Summer: subtropical segments are at their warmest and wettest. Afternoon thunderstorms in the southern half. Tidal range is at seasonal minimum; causeway crossings are generally more favorable. Northern segments are at their driest. Vegetation encroachment at maximum throughout.

Autumn: tropical storm risk in the southern third. Storm surge can submerge tidal marshland sections for days. Not recommended for the marshland segment during active storm periods. Northern segments: leaf fall improves visibility and overhead clearance. Stream crossings decreasing.

Winter: northern segments may ice. Road surfaces in the hardwood zone become slippery. Stream crossings at seasonal minimum throughout. Tidal range increases in winter; causeway fords deepen at high tide.

Network

This route has independent endpoints. The southern terminus is near the eastern origin of Gulf Lowland.

Gulf Lowland — the eastern origin of Gulf Lowland is accessible from the southern terminus via a short coastal connector. Approximately 80 km, not formally documented.
Great Plain — the terminus bridge of Great Plain is accessible from the piedmont segment via westward connector tracks. No documented traverse.

Revision

Route surveyed in full. Tidal marshland segment timed across multiple tidal cycles. Bridge conditions assessed individually. Overhead clearance measured at the constraint point. Former settlement zones documented for passable road surfaces only; no survey of structures conducted beyond what is visible from the route. Ford depths at seasonal median.