Hunter Lake is a proposed 2,649-acre (10.72 km2) reservoir to be created in Illinois, United States, by damming Horse Creek, a tributary of the Sangamon River.

[3] Despite the fact that capacity has never again precipitously dropped, and despite the fact that wildly inaccurate assessments of growth in population and demand that spiked the original planning have never materialized, calls for the construction of Hunter Lake as a supplemental water supply persisted, and in 1989, in the midst of a drought, resulted in passage of an ordinance to begin seeking necessary permits.

[1] As of 2016, the agencies prevented approval of the lake project three times due to flawed or inadequate studies required by the National Environmental Policy Act.

The ACE then requested that a supplemental environmental impact study (SEIS) be prepared before this permit application can be considered.

Hunter Lake concerns, raised by the Army Corps of Engineers in September 2011, included: (a) the age, in years, of the information contained in the original environmental impact study (EIS) submitted by CWLP, (b) changes and additions to EIS law that have taken place since the original EIS was submitted, (c) inadequate consideration of the adaptive re-use of existing Sangamon County gravel pits as a potential water storage capacity alternative, and (d) inadequate consideration of the drilling of groundwater wells into a Central Illinois aquifer or aquifers as a potential alternative supplemental water supply.

[6] Advocates and organizations opposed to Hunter Lake note that water demand has been flat for over 40 years and that CWLP's projections for high growth in population and demand are unjustified because the population is decreasing and because, by CWLP's own admission, closing three of it old water intensive power plants in 2021 increased the drought yield of Lake Springfield by 9.9 mgd.

Furthermore, they say if there is any need for a back-up supply, there are better, cheaper alternatives that do not have the devastating environmental impacts of Hunter Lake (such as destruction of two streams and surrounding forests, wetlands, prairie, agricultural land, and wildlife habitat).