<Tr> <Th_colspan="2"> Kilometre </Th> </Tr> <Tr> <Th> Unit system </Th> <Td> metric </Td> </Tr> <Tr> <Th> Unit of </Th> <Td> length </Td> </Tr> <Tr> <Th> Symbol </Th> <Td> km </Td> </Tr>

The si unit for length is the kilometre