The variation of the An-Cl bond distance in ground-state actinide trichloride (AnCl3) molecules have been studied by Density Functional Theory calculations using the B3LYP exchange-correlation functional in conjunction with small-core relativistic energy-consistent pseudopotentials for the actinides. The ground electronic states and the ground-state molecular properties of the trichlorides of heavy actinides (An = Bk?Lr) are reported in this paper the first time. Extending the present results with literature data on the light actinide trichlorides (AnCl3, An = Th-Cm), the trend in the bond distance has been evaluated for the whole actinide row. The contraction is well manifested in the major part of the actinide row (An = U-Fm). The deviations at the beginning (Th, Pa) and end of the row (Md, No) have been explained by minor differences in the bonding interactions.