Very long baseline interferometry (VLBI) has been used to measure three baselines of 150--300 km length within California and three baselines of 1500 km length between California and Texas. These measurements, which span nearly 4 years beginning in 1980 and have typical individual uncertainties of approximately 2 cm, have been fitted to a steady plane strain/rotation model. After solving for internal network strains and velocities with respect to the North American plate interior, the Jet Propulsion Laboratory site (35 km SW of the San Andreas fault trace) is found to move toward the northwest with respect to point >100 km NE of the fault, at an average rate of 25¿4 mm yr-1, along an azimuth of N40¿W¿7¿. No reliably determined motion is registered between the other sites, all of which are >100 km from the inferred Pacific-North American plate boundary. The observed rate of displacement across the San Andreas fault agrees with independent determinations of contemporary slip rates but appears to conflict with the rigid global plate tectonic rate. Differences between this rate determination and those from satellite laser ranging observations provide potentially important constraints on the distribution of tectonic strain in the region. These results are taken as evidence for a regional distribution of elastic strain that is offset in approximately the same sense and amount as the Big Bend of the southern San Andreas fault. Finite element simulations support the conjecture that tractions on the base of the crust that accompany mantle downwelling beneath the Transverse Ranges, could contribute to these strain inhomogeneities.