The densities of 0.00858-6.0141 mol(.)kg(-1) NaCl solutions were determined between 253 and 293 K with a capillary-tube densitometer. Among the data were the first density determinations of supercooled NaCl solutions. The greatest inaccuracy of the measured densities for the entire data set was 200 mug(.)cm(-3). Our densities were close to those calculated with the equation of state for the NaCl-H2O system of Archer. Apparent molal volumes of NaCl(aq) were calculated and fitted to the Pitzer equations, yielding estimated apparent molal volumes at infinite dilution and Pitzer volumetric parameters to 258 K. The values of these parameters from 273 to 298 K were in good agreement with the data of Rogers and Pitzer. From our experimental data we were able to calculate densities of very dilute to saturated sodium chloride solutions at temperatures down to 258 K.