This is USDA-ARS data from the publication: "Evaluation of Alternative-Design Cotton Gin Lint Cleaning Machines on Fiber Length Uniformity Index". The study was conducted in 2018 & 2019 with continued sample and data analysis through August 2023. Developing cotton ginning methods that improve fiber length uniformity index to levels that are compatible with the newer and more efficient spinning technologies would expand market share and increase the demand for cotton products and give U.S. cotton a competitive edge to synthetic fibers. Older studies on lint cleaning machines showed that the most widely used feed mechanism that places fiber on the cleaning cylinder damages fiber and reduces uniformity. The present study evaluates how conventional and experimental feed mechanisms affect uniformity. The lint cleaners were used with both saw and roller gin stands. Four diverse cotton cultivars from the Far West, Southwest, and Mid-South were used in the test. The data included gining process variables, raw seed cotton characteristics, raw lint High Volume Instrument (HVI), Advanced Fiber Information System (AFIS), and micro-dust and trash analyzer (MDTA3) measurements.