THE OREGON TRAIL (CHAPS 3-4) FORT LEAVENWORTH and JUMPING OFF

Chapter 3: Fort Leavenworth 
Arrival at the Frontier: After struggling up the Missouri River on a steamboat, Parkman and his party arrive at Fort Leavenworth. He describes the fort as a remote but orderly military outpost on the edge of the wilderness.
The Contrast of Life: Parkman observes the interaction between the disciplined U.S. military presence and the "wild" characters of the frontier, including Kansas Indians and various traders.
Logistics and Preparation: This chapter emphasizes the final stage of preparation before heading into "Indian Country." Parkman notes the bustling activity as emigrants and traders gather supplies, weapons, and livestock. 
Chapter 4: "Jumping Off"
The Chaos of Independence: Parkman visits the town of Independence, Missouri, which served as the primary "jumping-off point" for the trail. He finds the town crowded and overwhelmed by thousands of emigrants.
Lack of Leadership: He observes that while there are many parties of emigrants, they are in a state of "great confusion." They hold constant meetings and pass resolutions but struggle to agree on leaders or cohesive regulations for the journey.
Forming the Party: Desiring to avoid the slow and disorganized emigrant wagon trains, Parkman and his companion Quincy Adams Shaw finalize their own small group. They solidify their team, which includes their experienced guide Henry Chatillon and the muleteer Deslauriers.
Departure: The chapter concludes with the party finally leaving the settled frontier behind and pushing out onto the open prairie, marking the true beginning of their overland expedition.