Kelso is a market town in the Scottish Borders area of Scotland. Within the boundaries of the historic county of Roxburghshire, it lies where the rivers Tweed and Teviot have their confluence. The town has a population of 5,639 according to the 2011 census and based on the 2010 definition of the locality.
Kelso's main tourist draws are the ruined Kelso Abbey and Floors Castle, a William Adam designed house completed in 1726. The Kelso Bridge was designed by John Rennie who later built London Bridge.
Kelso is also notable for a long meteorological history. It held the UK record for lowest, official, January temperature at −26.7 °C, from 1881 until 1982. It also held the December record with the same temperature from 1879 to 1995.