The Souhegan River is a scenic waterway in southern New Hampshire, originating near New Ipswich and flowing approximately 34 miles northeast before joining the Merrimack River in Merrimack. This river system drains a watershed of about 171 square miles, encompassing parts of Hillsborough County. The Souhegan offers diverse paddling opportunities, from challenging whitewater to peaceful flatwater sections.

The upper reaches from Greenville to Wilton provide exciting Class II-III rapids, popular among intermediate to advanced paddlers during high water conditions in spring. The 5.75-mile stretch from Greenville to NH Route 101 Bridge and the subsequent 1.25-mile run to Wilton are particularly notable for their continuous rapids and technical challenges. Downstream, the river mellows, offering easier Class I-II paddling suitable for novices and families. The sections from Milford through Amherst to Merrimack provide pleasant flatwater experiences, with occasional gentle riffles. Popular routes include the 2.25-mile paddle from Route 122 to Amherst Canoeport, and the 2-mile stretch from Amherst Canoeport to Severns Bridge.

The Souhegan's flow is highly seasonal, with optimal paddling conditions typically occurring in spring and after heavy rains. Summer often brings lower water levels, though sections like Amherst to Merrimack usually remain navigable. Paddlers should check water levels before embarking, especially for the upper whitewater sections.

Wildlife enthusiasts may spot various bird species, deer, and possibly river otters along the shores. The river corridor supports a mix of hardwood forests and open fields, creating a picturesque backdrop for paddling adventures.

Key landmarks include the high NH 101 bridge near Wilton, offering a small Class II wave, and Wildcat Falls in Merrimack, a popular spot for kayaking and hiking. The river passes by Souhegan High School and through several historic mill towns, reflecting the area's industrial heritage.

Primary access points are found in Greenville, Wilton, Milford, Amherst, and Merrimack, with well-established put-ins and take-outs. The Amherst Canoeport on Boston Post Road serves as a central access point for many paddlers.

Safety considerations include potential strainers and fallen trees, particularly in the upper sections. Paddlers should be aware of dams, notably the Label Art dam in Wilton, which marks the end of the whitewater section. While primarily used for day trips, the Souhegan's length and variety of sections could accommodate multi-day adventures for those willing to arrange shuttles and camping. The river's proximity to towns allows for easy resupply and varied trip planning.

The Souhegan River offers a quintessential New England paddling experience, combining natural beauty, historical significance, and a range of paddling challenges suitable for various skill levels.