A line graph displays the population for each U.S. state during the month of January, with the x-axis representing states and the y-axis showing population values. The chart uses D3 v5 with React, rendering as an SVG. It loads CSV data from a GitHub gist via `d3.csv`, applies `scaleTime` and `scaleLinear` for axes, and draws the line using `d3.line`. Gridlines are created through axis tick sizes, with custom labels and a title styled via CSS.