What color or colors represent contour lines on a map?

On topographic maps, contour lines are primarily represented in brown. This color choice is standardized in cartography to distinguish these lines that connect points of equal elevation, making it easier to visualize the terrain's shape.

The option that includes both brown and red-brown acknowledges that variations in the brown color can occur due to map printing styles and the level of detail. Brown hues are typically used in delineating the elevation changes of terrain, while shades like red-brown can also appear, especially in older or specialized maps. This gives the map a clearer distinction against other geographical features depicted in different colors.

It's important to note that while red is sometimes utilized in various mapping contexts, it is not a standard color for contour lines. Yellow is generally reserved for highlighting other features on a map, like areas of interest or specific land uses.