{{Short description|State highway in Douglas County, Washington, US}} {{Use American English|date=May 2025}} {{Use mdy dates|date=January 2025}} {{Infobox road |state=WA |type=SR |route=172 |spur_type=SR |spur_of=17 |section=355 |map=Washington State Route 172.svg |map_notes=SR 172 highlighted in red |length_mi=35.01 |length_round=2 |length_ref=<ref name="log">{{WSDOT State Highway Log |year=2011 |pages=1164–1167 |link=yes |accessdate=January 15, 2013}}</ref> |established=1964<ref name="RCW">{{cite web |url=http://apps.leg.wa.gov/RCW/default.aspx?cite=47.17.355 |title=47.17.355: State route No. 172 |year=1970 |work=Revised Code of Washington |publisher=Washington State Legislature |accessdate=January 15, 2013}}</ref> |direction_a=West |terminus_a={{jct|state=WA|US|2}} near Waterville |direction_b=East |terminus_b={{jct|state=WA|SR|17}} near Leahy |counties=Douglas |previous_type=SR |previous_route=171 |next_type=SR |next_route=173 }}
'''State Route 172''' ('''SR 172''') is a {{convert|35.01|mi|km|2|adj=on}} long state highway serving rural Douglas County in the U.S. state of Washington. The highway travels north from U.S. Route 2 (US 2) near Waterville through Withrow and east through Mansfield before ending at SR 17 at Sims Corner. The highway follows the route of a county road built in the 1930s and signed as '''Secondary State Highway 10B''' ('''SSH 10B''') in 1955. SSH 10B became SR 172 during the 1964 highway renumbering and served a daily average of less than 700 vehicles in 2011.
==Route description== [[File:Main Street, Mansfield, WA.jpg|thumb|left|SR 172 passing through Mansfield as Main Street]]
SR 172 begins as Road C NW at an intersection with US 2 at the unincorporated community of Farmer, between Waterville and Coulee City. The highway travels north through farmland and serves Withrow before climbing Lone Butte and turning east into 14th Road NW.<ref name="log"/> SR 172 continues east into Mansfield, where it becomes Main Street and turns southeast into Downtown at Mansfield High School. The roadway turns northeast onto Railroad Avenue, serving the Mansfield Airport. SR 172 leaves Mansfield and continues east as 14th Road NE until it ends at SR 17 at Sims Corner, between Coulee City and Leahy.<ref name="google">{{google maps |title=State Route 172 |url=https://maps.google.com/maps?saddr=US-2+E&daddr=47.6452244,-119.8133973+to:WA-17+N%2FR+Rd+NE&hl=en&ll=47.714185,-119.58836&spn=0.250861,0.676346&sll=47.814379,-119.359567&sspn=0.007824,0.021136&geocode=Fc6C1gId3crb-A%3BFSgC1wId68rb-CkZSOJp4uybVDFJe8P_kZoxbA%3BFbua2QIdtavi-A&mra=me&mrsp=1,0&sz=16&t=m&z=11&via=1 |accessdate=January 15, 2013}}</ref><ref name="county-atlas">{{cite map |publisher=Douglas County Transportation & Land Services |title=Douglas County 2010 Road Atlas |date=April 2010 |url=http://www.douglascountywa.net/departments/tls/gis/Maps/DouglasCountyRoadAtlas.pdf |scale=1:16,000 |pages=111, 119 |edition=2010 |location=East Wenatchee, Washington |format=PDF |accessdate=January 15, 2013}}</ref>
Every year the Washington State Department of Transportation (WSDOT) conducts a series of surveys on its highways in the state to measure traffic volume. This is expressed in terms of annual average daily traffic (AADT), which is a measure of traffic volume for any average day of the year. In 2011, WSDOT calculated that between 200 and 690 vehicles per day used the highway, mostly in Mansfield.<ref name="ATR">{{cite web |author=Staff |year=2011 |title=2011 Annual Traffic Report |publisher=Washington State Department of Transportation |url=http://www.wsdot.wa.gov/mapsdata/travel/pdf/Annual_Traffic_Report_2011.pdf |page=152 |accessdate=January 15, 2013 |archive-date=June 13, 2013 |archive-url=https://web.archive.org/web/20130613043942/http://www.wsdot.wa.gov/mapsdata/travel/pdf/Annual_Traffic_Report_2011.pdf |url-status=dead }}</ref>
==History== thumb|right|SR 172 westbound at SR 17
A gravel county road extending from Lone Butte through Mansfield to Sims Corner first appeared in a 1933 Department of Highways map of Washington.<ref name="map1933">{{cite map |publisher=Department of Highways |title=Highway Map of the State of Washington |date=April 1, 1933 |url=http://www.sos.wa.gov/history/maps_detail.aspx?m=70 |format=DJVU |accessdate=January 15, 2013}}</ref> The road was paved and used temporarily by Primary State Highway 10 (PSH 10) until a Bridgeport–Leahy road was built to the northeast in the 1950s.<ref name="map1939">{{cite map |publisher=Department of Highways |title=Highways of the State of Washington |year=1939 |url=http://www.sos.wa.gov/history/maps_detail.aspx?m=28 |format=DJVU |accessdate=January 15, 2013}}</ref><ref name="leahy-bridgeport-road1949">{{cite news |date=April 2, 1949 |title=Chamber Session Broad in Scope |work=Spokane Daily Chronicle |publication-place=Spokane, Washington |url=https://news.google.com/newspapers?id=LfkZAAAAIBAJ&sjid=yPUDAAAAIBAJ&dq=bridgeport%20leahy%20highway&pg=6060%2C363548 |accessdate=January 15, 2013}}</ref> A paved road from Mansfield to Withrow and Farmer was built by 1950 and was signed as an extension of Secondary State Highway 10B (SSH 10B) in 1955.<ref name="law1955">{{cite book |author=Washington State Legislature |title=Session Laws of the State of Washington |edition=1955 |year=1955 |publisher=Washington State Legislature |location=Olympia, Washington}}</ref><ref name="usgs1953-map">{{cite map |publisher=United States Geological Survey |title=Ritzville, 1953 |year=1953 |url=http://www.lib.utexas.edu/maps/topo/250k/txu-pclmaps-topo-us-ritzville-1953.jpg |scale=1:250,000 |format=JPG |accessdate=January 15, 2013}}</ref> SSH 11B was split into SR 172 and SR 174 in the 1964 highway renumbering.<ref name="RCW"/><ref name="sr">{{cite web |last=Prahl |first=C. G. |title=Identification of State Highways |url=https://www.wsdot.wa.gov/sites/default/files/2005/04/26/Identification-of-state-highways.pdf |publisher=Washington State Highway Commission, Department of Highways |date=December 1, 1965 |accessdate=January 15, 2013 |archive-date=October 30, 2008 |archive-url=https://web.archive.org/web/20081030044024/http://www.wsdot.wa.gov/NR/rdonlyres/6836215D-E301-43F3-895A-472BD2FDE86A/0/Identification.pdf |url-status=dead }}</ref><ref name="usgs1965-map">{{cite map |publisher=United States Geological Survey |title=Ritzville, 1965 |year=1965 |url=http://www.lib.utexas.edu/maps/topo/250k/txu-pclmaps-topo-us-ritzville-1965.jpg |scale=1:250,000 |format=JPG |accessdate=January 14, 2013}}</ref>
==Major intersections== {{WAinttop|county=Douglas|length_ref=<ref name="log"/>}} {{WAint |location=none |mile=0.00 |road={{jct|state=WA|US|2|city1=Coulee City|city2=Waterville}} |notes=Western terminus}} {{WAint |location=none |mile=35.01 |road={{jct|state=WA|SR|17|city1=Coulee City|city2=Bridgeport|location3=Grand Coulee Dam}} |notes=Eastern terminus}} {{jctbtm}}
==References== {{reflist}}
==External links== {{AttachedKML|display=title,inline}} {{Commons category|Washington State Route 172}}
*[https://www.angelfire.com/wa2/hwysofwastate/sr172.html Highways of Washington State]
{{State highways in Washington related to SR 17}}
172 Category:Transportation in Douglas County, Washington