St. Ursen has a population () of . , 5.0% of the population are resident foreign nationals. Over the last 10 years (2000–2010) the population has changed at a rate of 7.2%. Migration accounted for 3.3%, while births and deaths accounted for 1.1%. Most of the population () speaks
German (1,045 or 89.9%) as their first language,
French is the second most common (103 or 8.9%) and
Portuguese is the third (6 or 0.5%). There are 2 people who speak
Italian. Of the population in the municipality, 469 or about 40.4% were born in St. Ursen and lived there in 2000. There were 460 or 39.6% who were born in the same canton, while 152 or 13.1% were born somewhere else in Switzerland, and 49 or 4.2% were born outside of Switzerland. , there were 415 private households in the municipality, and an average of 2.7 persons per household. , the construction rate of new housing units was 1.6 new units per 1000 residents. Colors= id:lightgrey value:gray(0.9) id:darkgrey value:gray(0.8) ImageSize = width:1080 height:210 PlotArea = height:150 left:100 bottom:50 right:100 AlignBars = justify DateFormat = x.y Period = from:0 till:1200 TimeAxis = orientation:vertical AlignBars = justify ScaleMajor = gridcolor:darkgrey increment:200 start:0 ScaleMinor = gridcolor:lightgrey increment:40 start:0 PlotData= color:yellowgreen width:40 mark:(line,white) align:center bar:1811 from:start till:668 text:"668" bar:1831 from:start till:751 text:"751" bar:1850 from:start till:685 text:"685" bar:1860 from:start till:892 text:"892" bar:1870 from:start till:940 text:"940" bar:1880 from:start till:977 text:"977" bar:1888 from:start till:1004 text:"1,004" bar:1900 from:start till:982 text:"982" bar:1910 from:start till:1067 text:"1,067" bar:1920 from:start till:1105 text:"1,105" bar:1930 from:start till:1073 text:"1,073" bar:1941 from:start till:1085 text:"1,085" bar:1950 from:start till:1139 text:"1,139" bar:1960 from:start till:1017 text:"1,017" bar:1970 from:start till:1027 text:"1,027" bar:1980 from:start till:1003 text:"1,003" bar:1990 from:start till:1066 text:"1,066" bar:2000 from:start till:1162 text:"1,162" ==Heritage sites of national significance==