This data -release component documents field portable X-ray fluorescence (pXRF) measurements of lead and associated quality-control data for 19 samples of paint chips collected from structures suspected to have legacy coatings of lead-based paint in Lakeport (Lake County, California) during July 11-12, 2022. Environmental samples were collected at selected sites to assess the effects of lead-based paint on soil chemistry. This sampling was made as part of a broader study to attribute sources of lead in soils in cooperation with the California Department of Toxic Substances Control (DTSC) for their Lead-Acid Battery Recycling Facility Investigation and Cleanup (LABRIC) program. Lead concentrations for paint chips measured by pXRF were used as a semi-quantitative screening tool to aid in selection of sites for soil and paint-chip sampling in addition to the age of structure and condition of exterior paint layers. A total of 34 measurements of lead concentration using pXRF for 19 samples of paint chips are included in this child item. Measurements were made on layered paint chips contained within low-density, polyethylene sample bags using a Thermo Niton XL5 pXRF instrument. Layered paint chip samples were scanned through both their inner and outer facing sides to assess relative lead contents of newer and older paint layers. Measurements on multiple paint chips from the same sample bag are presented for two samples. Field and laboratory measurements of standard reference materials with lead concentrations within the range of values measured for paint-chip samples had percent recoveries for lead concentration within 20 percent of the certified value. The same standard reference materials were measured in the laboratory inside 2 millimeter-thickness, low-density polyethylene sample bags and had percent recoveries for lead concentration within 20 percent of the certified value. Lead concentrations for paint chips analyzed by pXRF presented in this data release are reported in parts per million and rounded to one to two significant figures to provide conservative, order-of-magnitude estimates of apparent paint-chip lead concentrations. Apparent lead concentrations for layered paint chips are not representative of the concentration of paint in an individual paint layer, as the density and thickness of different paint layers with different elemental compositions can influence pXRF results (McKnight and others, 1989). This data release contains two tab-delimited text files. The "Lakeport_paint.txt" file contains field pXRF measurements of lead for paint-chip samples. The "Lakeport_pXRF_QC.txt" file contains quality control data for pXRF measurements of lead for four National Institute of Standards and Technology (NIST)-certified standard reference materials.