Proper motions of extragalactic jets, primarily conducted with very long baseline interferometry (VLBI), have revealed that these jets have bulk relativistic velocities which can exceed 99.999% the speed of light (Lorentz factors up to ~80). The parsec-scale proper motions traced by VLBI observations, however, often show a flow that is still accelerating on these scales. The measurement of the full velocity profile of jets from parsec to kiloparsec scales has only been done for a handful of jets, owing to the difficulty of obtaining decades-long time baselines for comparison on the larger (kiloparsec) scales. The Very Large Array (VLA) has now been in operation for over 40 years, and the NRAO hosts a very rich archive of observations of extragalactic jets. I will present a new effort to mine the VLA archives to measure the proper motions of jet plasma on kilo-parsec scales, where I have analyzed archival VLA observations of radio-galaxies 3C78 and M87 for proper motions. For 3C78 we detect for the first time proper motions for multiple knots with speeds of 0.1-0.5c. Although sub-luminal, we find that the average kiloparsec velocity is ~ 3 times higher than the VLBI speeds, in keeping with observations of M87 and 3C 264 which have showed that the fastest bulk speeds in these FR I jets are reached on the > 100 parsec scale. I will conclude with a discussion of the prospects for radio and sub-mm wavelength proper-motion studies of jets and the large catalog we intend to build using new and archival data.