Fluorescein and Rhodamine WT dye-tracer injections were performed in Monroe County, West Virginia to determine groundwater flow paths and identify the location of the groundwater divide within the Greenbrier karst aquifer in the area south of Union, West Virginia. Fluorescein was injected in a swallet on Burnside Branch upstream of Steel's cave (37° 33' 56.0" latitude -80° 32' 57.6" longitude) and Rhodamine WT was injected into a swallet at the contact of the Hillsdale Limestone and Maccrady Shale in the headwaters of Taggart Branch (37° 33' 17.8" latitude -80° 28' 29.0" longitude). Data collected from these tracer injections supported interpretations made by Jones (1997) with some refinements. The first table contains concentration of Fluorescein dye recovered at Dickson Spring in micrograms per liter (µg/L), mass of dye recovered at Dickson Spring in micrograms (µg) for each 8-hour sample, a cumulative running total mass of dye recovered at Dickson Spring in µg, and percent recovery of dye at Dickson Spring. Data were collected on an 8-hour interval with an automated sampler, so time of collection for each sample is denoted for each sample. Percent recovery is based on using one discharge measurement of 6.87 cubic feet per second (cfs) near the end of the recovery period. The second table contains concentration of Rhodamine WT in µg/L dye recovered at two sites: the resurgence from Steel's Cave and in Indian Creek at Salt Sulphur Springs, along with a cumulative running total mass of dye recovered at Steel's Cave in µg, and percent recovery of dye recovered at Steel's Cave. Data were collected manually once per day usually in midafternoon, but actual collection times of samples were not reported. The percent recovery calculation assumed a constant discharge at the spring of 0.59 cfs based on one measurement during the recovery period. It could not be determined whether dye detected in Indian Creek at Red Sulphur contained additional emergence or was simply the mass of dye that discharged upstream at the outlet from Steel's Cave. As a result, the mass, running cumulative total amount, and percent of dye recovery were not calculated for the Indian Creek at Salt Sulphur Springs monitoring site. Results of the tests, including a map showing locations of tracer injection and monitoring points, dye travel paths, previous tracer tests conducted in Monroe County, and a refinement of karst groundwater basins defined within the Greenbrier aquifer by Jones (1997) are presented in the accompanying USGS Scientific Investigations Report 2023-5121 to this data release. This data release contains two comma-delimited data files. Fluorescein_Data.csv contains data for select samples collected in Monroe County, West Virginia, in August and September 2019. Rhodamine_WT_Data.csv contains data for a tracer test conducted in Monroe County, West Virginia, July 2019.