Probing the galaxy with pulsar parallaxes and proper motions

The Very Long Baseline Array has enabled submilliarcsecond astrometry for a large sample of pulsars, and a program to at least double the number of measured pulsar parallaxes is now underway. New parallaxes and proper motions will enable a range of scientific applications, including accurate modeling of the velocity distribution of pulsars, calibrating models of Galactic electron density and the local interstellar medium, establishing constraints on the neutron star Equation of State, and the verification of reference frame ties and supernova remnant associations. We discuss the use of bow shock nebulae and pulsar scintillation and scattering observations to probe the interstellar medium, introduce a new model of the Galactic electron density distribution, and provide a road map for future observations.