We present Submillimeter Array observations of several deuterated species in the disk around the classical T Tauri star TW Hydrae at arcsecond scales, including detections of the DCN image and DCO super(+) image lines and upper limits to the HDO image, ortho-image, and para-image transitions. We also present observations of the HCN image, HCO super(+) image, and H super(13)CO super(+) image lines for comparison with their deuterated isotopologues. We constrain the radial and vertical distributions of various species in the disk by fitting the data using a model where the molecular emission from an irradiated accretion disk is sampled with a two-dimensional Monte Carlo radiative transfer code. We find that the distribution of DCO super(+) differs markedly from that of HCO super(+). The D/H ratios inferred change by at least 1 order of magnitude (0.01-0.1) for radii <30 to >=70 AU, and there is a rapid falloff of the abundance of DCO super(+) at radii larger than 90 AU. Using a simple analytical chemical model, we constrain the degree of ionization, image, to be image10 super(-7) in the disk layer(s) where these molecules are present. Provided the distribution of DCN follows that of HCN, the ratio of DCN to HCN is determined to be image ; however, this ratio is very sensitive to the poorly constrained vertical distribution of HCN. The resolved radial distribution of DCO super(+) indicates that in situ deuterium fractionation remains active within the TW Hydrae disk and must be considered in the molecular evolution of circumstellar accretion disks.