Detection apparatus, detection method, exposure apparatus, exposure system, and article manufacturing method

A detection apparatus that detects a mark formed on a substrate, comprising:

• a stage that moves while holding the substrate;
• a detection optical system that irradiates light on the mark on the substrate held by the stage and detects an image of the mark;
• and
• a processor that performs a detection process of the mark based on the image of the mark detected by the detection optical system,
• wherein the processor is configured to:
• find a detection value indicating a position of the mark in an observation field of the detection optical system based on the image of the mark detected by the detection optical system,
• find a subregion in which the mark is located among a plurality of subregions in the observation field, and
• correct the detection value based on a correction value corresponding to the found subregion among correction values predetermined for the plurality of subregions, respectively.