The issue of document fraud has continued to plague the United States immigration system and compromises the integrity of case reviews as well as delays its legal procedures, adding extra responsibilities to the immigration officers. Depending on manual verification and isolated databases, traditional document-verification approaches risk being forged, tampered with and inefficient. There is an acute need to find adopt a secure, transparent, and tamper-proof document authentication system to handle the constantly growing volume of immigration cases faced and complexity of authenticating the documents filed in immigration proceedings. In this article, the DocAuthChain: a document authentication framework utilizing blockchain technology is proposed, designed with special consideration of the case processing system in the U.S. immigration agencies. Building on the distributed and tamper free blockchain technology, DocAuthChain guides and strengthens the authenticity and verifiability of important documents like birth certificate, academic records, legal affidavits and police clearances. It has built in smart contracts to automate verification procedures and has a permissioned block chain to retain confidentiality but permit authorised stakeholders like immigration officers, legal representatives and government agencies to access and verify records effectively in real time. The methodology introduces a modular system design including USCIS systems integration/third part verifier integration points. The simulation of cases proves that the DocAuthChain can help to decrease the time necessary to verify the documents, identify falsified documentation, and improve the level of trust among all parties. Implementation is tested in performance terms like the speed of authentication, detection of errors, and scalability of the system. Findings show that due to DocAuthChain, the number of administrative barriers is greatly limited and the security increases in verification. In addition to immigration, the system proposed can find application in legal, academic and medical document authentication. The given contribution helps take a giant step towards digital trust in state bodies and provides the means towards further policy-based blockchain implementation into governmental infrastructure.