Non-steady-state locomotion involving complex ambulation tasks, such as changing directions, walking over an obstacle, or moving from one terrain to another, are frequently presented in everyday life. These motor tasks that occur at home and within the community are often difficult to execute for individuals with neuromuscular conditions, where reduced dexterity and cognition hinder task planning and performance. Parkinson’s disease is characterized by restrictive gait patterns, such as tremors, increased limb stiffness, and impaired balance, which typically are exacerbated when completing complex tasks. Early diagnosis is critical for individuals with Parkinson’s disease to begin exercise programs and other therapies that can assist with slowing the progression of the disease. Optical gait analysis is a research tool that can be used to quantify kinematic differences within 1 mm of precision of those with motor impairments compared to healthy individuals. It also has the potential to be used in clinical settings to assist with the diagnosis of Parkinson’s disease for people still in the early stages of the disease when symptoms are not yet outwardly perceptible. My research analyzed the joint angles and joint ranges of motion of the hips, knees, and ankles of individuals with early-stage Parkinson’s disease compared to a healthy control group as they walked continuously on a terrain circuit that integrated a level ground walkway, staircase, turn, and ramp. It was hypothesized that since individuals with Parkinson’s disease are challenged by internal regulation of their mechanics, these complex tasks and corresponding analysis would reveal inherent kinematic differences during specific terrains or transitions. Additionally, we hypothesized that of the events analyzed, transitional events (i.e., moving from one terrain to another) would be more prone to cause deviations from control subjects due to the higher neuromechanical demand required. One stride was analyzed during each transitional or non-transitional event, identifying the joint angles and total joint ranges of motion (ROM). Four of the twelve events had a statistically significant difference (α = 0.05) between groups. Individuals with Parkinson’s disease displayed greater hip ROM during ramp ascent, less knee ROM during ramp ascent to the turn transitions and stair ascent to the turn transitions, and less hip ROM during ramp descent to level-walking transitions. Reduced knee flexion also revealed decreased stride length when approaching the turn and was associated with a higher number of steps taken to complete the transition. Differences in hip ROM, when ascending and transitioning off of the ramp, suggested that the unconstrained manner of ramp ambulation (relative to the stairs) presents individuals with Parkinson’s disease a greater challenge, perhaps due to an increased motor redundancy for task planning. Collectively, our analyses show that these common types of complex lower-limb tasks can be distinguished even at the early stages of Parkinson’s disease, and could assist in slowing its progression.