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We present 19 nearby (z<0.3) 3CR radio galaxies imaged at low- andhigh-excitation as part of a Cycle 15 Hubble Space Telescope snapshot surveywith the Advanced Camera for Surveys. These images consist of exposures of theH-alpha (6563 \AA, plus [NII] contamination) and [OIII] 5007 \AA emission linesusing narrow-band linear ramp filters adjusted according to the redshift of thetarget. To facilitate continuum subtraction, a single-pointing 60 s line-freeexposure was taken with a medium-band filter appropriate for the target'sredshift. We discuss the steps taken to reduce these images independently ofthe automated recalibration pipeline so as to use more recent ACS flat-fielddata as well as to better reject cosmic rays. We describe the method used toproduce continuum-free (pure line-emission) images, and present these imagesalong with qualitative descriptions of the narrow-line region morphologies weobserve. We present H-alpha+[NII] and [OIII] line fluxes from aperturephotometry, finding the values to fall expectedly on the redshift-luminositytrend from a past HST/WFPC2 emission line study of a larger, generally higherredshift subset of the 3CR. We also find expected trends between emission lineluminosity and total radio power, as well as a positive correlation between thesize of the emission line region and redshift. We discuss the associatedinterpretation of these results, and conclude with a summary of future workenabled by this dataset.

HST/ACS Emission Line Imaging of Low Redshift 3CR Radio Galaxies I: The Data