This study determined lethal dose levels of road salt on selected macroinvertebrates from a Michigan, USA wetland under different testing conditions and related those levels to in situ chloride concentrations of standing water habitats along multi-lane highways. We conducted simultaneous acute (24 and 96 h) and chronic (15 d) toxicity experiments using laboratory containers, containers adjacent to a wetland, and in situ modular field PVC microcosms. Data showed that Callibaetis fluctuans, Physella integra, Hyallela azteca, and Chaoborus americanus had relatively high tolerance to elevated road-salt levels. Depending on test condition, road-salt 96 h LC₅₀ estimates ranged from greater than 5000 mg l⁻¹ (2558 mg l⁻¹ Cl⁻) to >10,000 mg l⁻¹ (4502 mg l⁻¹ Cl⁻) road salt for C. fluctuans and P. integra, respectively. For H. azteca and C. americanus, mortality was generally low at all salt concentrations, with road-salt 96 h LC₅₀ estimates >10,000 mg l⁻¹. Chloride concentrations of 43 impacted Michigan wetlands ranged from 18 to 2700 mg l⁻¹ Cl⁻¹, with 75% <334 mg l⁻¹, indicating that macroinvertebrate LC₅₀ chloride estimates for the study species are well above most concentrations of the 43 wetlands.