This thesis presents a comprehensive exploratory analysis of truck route choice diversity in the state of Florida, for both long-haul and short-haul truck travel segments. We employ six metrics to measure three different dimensions of diversity in truck route choice between any given origin-destination (OD) pair. These dimensions are: (1) number of distinct routes used to travel between the OD pair, (2) the extent of overlap (or lack thereof) among the routes, and (3) the evenness (or the dominance) of the usage of different unique routes. The diversity metrics were utilized to examine truck route choice diversity from over 73,000 truck trips that were derived from over 200 million GPS records of a large truck fleet. Descriptive analysis and statistical modeling of the diversity metrics offered insights on the determinants of various dimensions of truck route choice diversity between an OD pair. The results could be used to improve choice set generation algorithms for truck route choice modeling as well as in planning truck route policies and investments.