This paper introduces the Matriliny Intensity Index (MII), a seven-variable quantitative instrument for measuring the structural intensity of matrilineal kinship organization at the community and district level across the Indian subcontinent and adjacent regions. The index operationalizes kinship gradient as a scoreable, falsifiable, and geographically mappable variable. Seven dimensions are scored on a 0–2 ordinal scale covering inheritance mode, residence pattern, marriage transfer direction, women's presence in land records, female economic and legal agency, clan naming convention, and polyandry. Scores are normalized to a 0–10 index. The index is applied in a pilot study to twenty-five community entries drawn from three independent sources within a single census year: Risley's Census of India 1901, Volume I: Ethnographic Appendices; N. Subramhanya Aiyar's Census of India 1901, Volume XXVI: Travancore; and B.C. Allen's Census of India 1901, Volume IV: Assam. MII scores range from 0.0 (Rajput, Prabhu) to 9.3 (Nayar of Malabar). Cross-source reliability is confirmed for three communities: the Nayar (9.3 from both Risley Vol. I and Aiyar Vol. XXVI), the Khasi (7.9 from both Risley Vol. I and Allen Vol. IV), and the Garo (8.6 confirmed independently). The results confirm a measurable kinship gradient inversely correlated with depth of Indo-Aryan cultural penetration. A structurally consistent partial-enclosure plateau (MII 2.1–2.9) spans eleven communities across Chota Nagpur, the Northeast frontier, Mizoram, and Upper Burma. The gap between MII 3.6 and 7.9 documented in prior single-source analysis is partially bridged by four Kerala/Assam communities from Vols. XXVI and IV: Pulayan (4.3), Mappila (5.0), Ezhava (5.7), and Garo (8.6). Two previously missing findings are reported: the Islamic natural experiment (the Mappila community, confirming the mechanism is economic rather than cultural) and the propertyless matriliny observation (the Pulayan, confirming the matrilineal substrate penetrates the bonded laborer class). All raw extraction matrices are reproduced in Appendix A. Keywords: matriliny, kinship gradient, South Asia, colonial ethnography, MII, Risley 1901, Dayabhaga, Marumakkathayam, bride price, partial enclosure, Islamic natural experiment