The Pulmonary Fibrosis Foundation Patient Registry will collect data on at least 2,000 patients with interstitial lung disease (ILD) at approximately 40 clinical sites in the US. The Registry is targeting enrollment of approximately 60% of the 2,000 ILD participants to have idiopathic pulmonary fibrosis (IPF). The aim of the Registry is to create a cohort of well-characterized patients with interstitial lung disease (ILD) for participation in retrospective and prospective research.