The Township of Bonnechere Valley, a lower‑tier municipality in Renfrew County with its centre at Eganville, was formed on January 1, 2001, through the amalgamation of the village of Eganville and the townships of Grattan, Sebastopol, and South Algona. Spanning roughly 588 km² and home to just under 3,900 residents (2021 census), it encompasses a variety of communities—from historic Anglophone and immigrant settlements to ghost town remnants—woven through a dynamic riverine landscape.

Long before municipal restructuring, the Bonnechere River shaped settlement patterns here: first as a transportation and timber corridor since the 1840s, most notably after John Egan built a grist mill and harnessed the river’s power at the Fifth Chute in Eganville. That industrial origin anchored survey frameworks, with Crown‑granted concessions and sideroads laid to serve the mills and associated communities.

Field survey practice across Bonnechere Valley today must reconcile multiple cadastral layers:
• The original mid‑19th‑century concession grids across Grattan, Sebastopol and South Algona;
• Industrial parcels and mill-site subdivisions tied to the river’s chutes;
• Later recreational lot severances around lakes and riverbanks;
• And modern road allowances paralleling concession alignments.

Geologically, the region sits within the Ottawa–Bonnechere Graben—a rift valley carved during Proterozoic to Paleozoic events—subsequently deepened by glacial melt and post‑glacial rebound. Its relatively flat valley floors contrast with rugged surrounding uplands and hold sediment‑rich soils and infrastructure that demand precision in elevation‑aware surveying, especially where active fault‑zone clay weights on shoreline and floodplain mapping.

From a land surveyor’s perspective, Bonnechere Valley exemplifies the complex layering of Ontario cadastral evolution: from Crown survey grids and industrial river alignments to modern recreational severances and geotechnical nuances of a graben‑influenced landscape. Surveying here involves cross‑referencing historical plats, hydro‑industrial maps, geological assessments, and creek‑river flood easements—a multi‑modal approach that highlights the continuing legacy of its environmental and settlement history.