 sibley is a city in osceola county, iowa, united states. the population was 2,798 at the 2010 census. it is the county seat of osceola county. hawkeye point, the highest point in the state of iowa, is also nearby. ==history== sibley had its start in the year 1872 by the building of the sioux city & st. paul railroad through that territory. it is the oldest town in osceola county.{{cite book | url=http://books.google.com/books?id=tftaaaaayaaj&pg=pa59
Cities_in_Iowa Cities_in_Osceola_County,_Iowa County_seats_in_Iowa