  Accurate distances to galaxies can be determined from the luminosities of
stars at the Tip of the Red Giant Branch (TRGB). We use a Maximum Likelihood
algorithm to locate the TRGB in galaxy color-magnitude diagrams. The algorithm
is optimized by introducing reliable photometric errors and a completeness
characterization determined with artificial star experiments. The program is
extensively tested using Monte-Carlo simulations, artificial galaxies, and a
sample of nearby dwarf galaxies observed with HST/WFPC2 and ACS. Our procedure
is shown to be reliable, to have good accuracy, and to not introduce any
systematic errors. The methodology is especially useful in cases where the TRGB
approaches the photometric limit and/or the RGB is poorly populated.
