Experimental p-rho-T data are reported for 1-(2-methoxyethyl)-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([MOEMPYR] [NTf2]), and two ionic liquids with thiocyanate ([SCN]) anion and 1-C-n-3-Methylimidazolium ([CnMIM]) cation with n = 2 and 4, which are still poorly studied in this respect. The data were obtained by using (i) a constant volume apparatus at temperatures from (218 to 353) K at nominal pressures of 1 MPa and from (10 to 50) MPa with a 10 MPa step, and (ii) tensiometer Kruss using buoyancy method at the pressure of 0.1 MPa and at temperatures from (262 to 365) K. Thus, the temperature and pressure region covered with experimental p-rho-T data has been substantially extended to lower temperatures for [C4MIM][SCN] and [MOEMPYR] [NTf2] and to higher pressures for [C2MIM]-[SCN] and [C4MIM][SCN]. The expanded combined uncertainty at the 0.95 confidence level of the reported isochoric densities takes its maximum value at the lower end of the temperature interval of the data, namely, from 1.2 kg.m(-3) for [C2MIM] [SCN] to 1.7 kg.m(-3) for [MOEMPYR] [NTf2], which is about 10.10(-3) rho. The global topology of the liquid-state region in, the internal pressure-specific volume plane is determined by presence or absence of the hydrogen bonding in the liquid.