Patients with Crohn's disease (CD) experience disease progression over time, including strictures/stenoses, penetrating fistulae, and abscesses. This retrospective US population-based study aimed to characterize CD progression in newly diagnosed patients. Patient-level data from the Optum® Market Clarity database from January 1, 2016, to June 30, 2020, were used. The study comprised a 12-month baseline period (pre-diagnosis), an index date (diagnosis date), and a follow-up period. The risk of, and time to, CD progression since CD diagnosis, dispensed treatment changes following CD progression, and healthcare resource utilization before and after CD progression were assessed. Overall, 6804 newly diagnosed patients were included. Of these, 1714 (25.2%) experienced CD progression as follows: 19.3% (1183/6117) in the first 6months, 21.6% (1188/5503) by 1year, 24.6% (953/3875) by 2years, and 26.6% (444/1668) by 3years. Intestinal obstruction/stenosis was more common than fistula or abscess. Among patients with CD progression, the median (interquartile range) estimated time to progression was 2 (0-140) days; the shortest time to progression was seen with a first intestinal obstruction/stenosis (0 [0-137] days). The frequency of several dispensed treatments increased following CD progression. Among patients who experienced progression, CD-related inpatient hospital admissions/visits increased from 436 of 1714 patients (25.4%) in the month before progression to 965 (56.3%) in the month after progression. Over one quarter of patients with newly diagnosed CD experienced CD progression and complications within 3years of diagnosis, highlighting the importance of monitoring for progression and early intervention to limit progression.