Infrastructure tools to support an effective radiation oncology learning health system

Saru (沙流郡, Saru-gun, Ainu: Sar) is a district located in Hidaka Subprefecture, Hokkaido, Japan.

As of 2004, the district has an estimated population of 21,190 and a density of 12.21 persons per km². The total area is 1,735.83 km².

• Biratori 42°35′06″N 142°07′43″E / 42.585115°N 142.128639°E / 42.585115; 142.128639 (town office)
• Hidaka 42°28′49″N 142°04′28″E / 42.480296°N 142.074389°E / 42.480296; 142.074389 (town office)

• On March 1, 2006, the town of Monbetsu merged into the expanded town of Hidaka.^[1]

42°31′58″N 142°06′05″E / 42.5327055°N 142.101514°E / 42.5327055; 142.101514 (average of town offices)