As described by the U.S. Coast and Geodetic Survey in 1953:
"AT AUSTIN, AT THE INTERSECTION OF SAN JACINTO BOULEVARD AND EAST 19TH STREET, 122 FEET WEST OF A STREET LIGHT, 35 FEET NORTH OF THE CENTER LINE OF SAN JACINTO BOULEVARD, SET IN THE TOP OF THE NORTH GUARD RAIL OF A CONCRETE BRIDGE OVER WALLER CREEK, 14.8 FEET EAST OF THE WEST END OF THE GUARD RAIL, 4.5 FEET ABOVE THE LEVEL OF THE STREET. 210 FEET NORTHEAST OF THE CENTER OF THE STREET INTERSECTION."
The CGS description is pretty accurate and still holds up to this day (although "19th Street" is called "MLK Blvd nowadays): on top of the northern guard rail of San Jacinto Blvd when it crosses over Waller Creek, NW corner of that bridge. See one of the gallery images which includes a red arrow for a visual reference.
The original monumented coordinates, however, are slightly off (as is to be expected, it happens all the time with older benchmarks). The NGS datasheet reports it at "N 30 16.817 W 097 44.100" which points to the center of the bridge (and on the street/pavement), ~90 feet away from the benchmark in question. The actual coords -- as personally measured within 11-12' accuracy, and as measured by several previous visitors before me who reported their findings on www.geocaching.com as well -- are "N 30 16.819 W 097 44.117".
Below are some additional facts, per the NGS database (with some editing for length): (
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BM0583 ***********************************************************************
BM0583 DESIGNATION - X 804
BM0583 PID - BM0583
BM0583 STATE/COUNTY- TX/TRAVIS
BM0583 COUNTRY - US
BM0583 USGS QUAD - AUSTIN EAST (1988)
BM0583
BM0583 *CURRENT SURVEY CONTROL
BM0583 ______________________________________________________________________
BM0583* NAD 83(1986) POSITION- 30 16 49.14 (N) 097 44 06.76 (W) HD_HELD1
BM0583* NAVD 88 ORTHO HEIGHT - 155.162 (meters) 509.06 (feet) ADJUSTED
BM0583_MARKER: DB = BENCH MARK DISK
BM0583_SETTING: 36 = SET IN A MASSIVE STRUCTURE
BM0583_SP_SET: BRIDGE
BM0583_STAMPING: X 804 1953
BM0583_MARK LOGO: CGS
BM0583_STABILITY: B = PROBABLY HOLD POSITION/ELEVATION WELL
BM0583_SATELLITE: THE SITE LOCATION WAS REPORTED AS NOT SUITABLE FOR
BM0583+SATELLITE: SATELLITE OBSERVATIONS - March 01, 2007
BM0583
BM0583 HISTORY - Date Condition Report By
BM0583 HISTORY - 1953 MONUMENTED CGS
BM0583 HISTORY - 1980 GOOD NGS
BM0583 HISTORY - 19860619 MARK NOT FOUND USGS
BM0583 HISTORY - 1990 GOOD USPSQD
BM0583 HISTORY - 20010224 GOOD USPSQD
BM0583 HISTORY - 20020225 GOOD NGS
BM0583 HISTORY - 20030308 GOOD USPSQD
BM0583 HISTORY - 20050226 GOOD USPSQD
BM0583 HISTORY - 20070301 GOOD USPSQD