Micropost arrays are a valuable platform for studying cell migration in controlled microenvironments. These arrays enable researchers to mimic how migrating cells deform their nuclei in reaction to physical constraints presented by extracellular matrix (ECM) fibers during processes such as wound healing and cancer metastasis. By tuning micropost patterns and sizes, researchers can not only explore the impact of confining spaces created by such patterns on cell migration, signaling, and nuclear deformation but also simultaneously quantify cell-generated forces and forces of nuclear deformation. This paper outlines methods to design and fabricate ECM fiber mimicking micropost arrays for use in fundamental studies of confining cell migration.