Texas State Highway Spur 78

State Highway Spur 78
Route information
Maintained by TxDOT
Length:	1.547 mi[1] (2.490 km)
Existed:	Before 1939 – present
Major junctions
South end:	Mt. Locke summit, McDonald Observatory
	Spur 77
North end:	SH 118
Location
Counties:	Jeff Davis
Highway system
Highways in Texas Interstate US State Toll Loops Spurs FM/RM Park Rec ← Spur 77 Spur 79 →

Spur 78 descending Mt. Locke at McDonald Observatory. Spur 77 ascends Mt. Fowlkes in the distance.

Texas State Highway Spur 78 or Spur 78 is a spur road maintained by the Texas Department of Transportation (TxDOT) connecting the University of Texas at Austin's McDonald Observatory complex atop Mt. Locke to State Highway 118 15.2 miles (24.5 km) from Fort Davis.^[2] The road is 1.5 miles (2.4 km) long and is located within Jeff Davis County.

History

Spur 78 was not included on the 1933 official state highway map,^[3] but was in existence by 1939 when both the observatory was dedicated^[4] and the state's Highway Designation Files were created.^[1] Before 1941, the road connected the observatory to SH 166 until the section of that route between Fort Davis and the current intersection of SH 118 and SH 166 was re-designated as part of SH 118.^[5] In 1991 the only other intersecting highway, Spur 77, was created.^[6]

Route description

Elevation sign at terminus of Spur 78 atop Mt. Locke at McDonald Observatory

At its terminus at the summit of Mt. Locke, Spur 78 has the distinction of having the highest elevation at any point on the state highway system with an elevation of 6,791 feet (2,070 m).^[7] The route begins in front of the Otto Struve Telescope and Harlan J. Smith Telescope where there is a scenic overlook of the valley below and the surrounding Davis Mountains.

Initially the route has steep grades as it descends from the summit of the mountain. After 0.5 miles (0.8 km) the route intersects Spur 77 toward nearby Mt. Fowlkes where the observatory has another cluster of facilities. Spur 78 also intersects a few observatory service roads to maintenance facilities and residential areas. The observatory passes by the observatory's Frank N. Bash Visitors Center before terminating at SH 118.

Major intersections

The entire route is in McDonald Observatory, Jeff Davis County.

mi[8]	km	Destinations	Notes
0	0.0	Mt. Locke summit	Southern terminus
0.5	0.80	Spur 77	Mt. Fowlkes spur
1.5	2.4	SH 118	Northern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

See also

• U.S. Roads portal
• Texas portal

References

1. Transportation Planning and Programming Division (n.d.). "State Highway Spur No. 78". Highway Designation Files. Texas Department of Transportation. Retrieved 2009-12-12.
2. Google (2009-12-12). "SH 118 between Fort Davis and Spur 78" (Map). Google Maps. Google. Retrieved 2009-12-12.
3. Texas State Library and Archives Commission, Official Map of the Highway System of Texas, 1933
4. Evans, David S. (2009-11-11). "University of Texas at Austin McDonald Observatory". The Handbook of Texas Online. Texas State Historical Association. Retrieved 2009-12-12.
5. Transportation Planning and Programming Division (n.d.). "State Highway No. 166". Highway Designation Files. Texas Department of Transportation.
6. Transportation Planning and Programming Division (n.d.). "State Highway Spur No. 77". Highway Designation Files. Texas Department of Transportation.
7. "Mount Locke Summit, near Fort Davis, Texas 6791 Ft - Elevation Signs on Waymarking.com". Groundspeak, Inc. Retrieved 2009-12-12.
8. Google (2009-12-12). "Route of Spur 78" (Map). Google Maps. Google. Retrieved 2009-12-12.

External links

Route map: Bing / Google

Geographic data related to Texas State Highway Spur 78 at OpenStreetMap

• McDonald Observatory website