Loop 473 was designated along an old alignment of US 281 on January 31, 1969, through the city when US 281 was relocated along the Henry S. Grace Freeway. At first, the Loop 473 designation was a hidden, internal one as the route was publicly signed as Bus. US 281 while the route originally terminated at its northernintersection with US 281. The Loop 473 designation became public after the route was extended northward on September 14, 1973, to the former Loop 370. Loop 370 itself was only an internal TxDOT designation publicly signed as a US 287business route until that route formally became Business US 287-J in 1991.