Location: US-87 and Hastings Ave, Amarillo After the Loop 335 junction, we’ll get our first IH 27 reference. Follow 27 south to get to Palo Duro Canyon. Location: US-87 and River Rd, Amarillo Reassurance shield after the Loop 335 and Hastings St interchanges. Just around this corner Loop 434 will merge back on without signage. … Continue reading U.S. Route 87, TX-335 Loop to TX-434 Loop