The Naval Observatory Vector Astrometry Software (NOVAS) is an integrated package of subroutines and functions for computing various commonly needed quantities in positional astronomy. The package can supply, in one or two subroutine or function calls, the instantaneous coordinates of any star or planet in a variety of coordinate systems. At a lower level, NOVAS also provides astrometric utility transformations, such as those for precession, nutation, aberration, parallax, and gravitational deflection of light. The computations are accurate to better than one milliarcsecond. The NOVAS library is an easy-to-use facility that can be incorporated into data reduction programs, telescope control systems, and simulations.The U.S. parts of The Astronomical Almanac are prepared using NOVAS.