Submonolayer coverages of Cs adsorbed at room temperature on the GaAs(110) surface are examined with scanning tunneling microscopy. Linear chains, formed by two adjoining rows of Cs atoms, are observed along the [11̄0] direction for coverages as low as 0.03 monolayer. The one-dimensional Cs chains are observed to be several hundred Å long, and are seen in images of both the occupied and unoccupied electronic states. At higher coverages, approaching 0.15 monolayer, stable linear structures consisting of three neighboring Cs rows have been found.