At least 2,000 patients with interstitial lung disease (ILD) at approximately 40 clinical sites in the US. The Pulmonary Fibrosis Foundation Patient Registry will collect data on at least 2,000 patients 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 fibrosos (IPF).