Federal Lands Administration Act of 1986 - Title I: Purposes, Definitions, and Maps - Sets forth the purposes, definitions, and maps which delineate the areas of lands affected by this Act. Title II: Transfer of Lands to the Forest Service - Transfers lands delineated on the maps entitled "Interagency Land Transfers -- February 1986" to the Secretary of Agriculture to be reserved as national forests. Authorizes the Secretary to modify the boundaries of National Forest System units to facilitate administration. Requires newly established national forest lands to be eventually managed in accordance with the Forest and Rangeland Renewable Resources Planning Act of 1974. Directs the Secretary to adopt the recommendations of the Secretary of the Interior with respect to such lands which have been reviewed for wilderness suitability and to assess unreviewed lands for their possible designation as wilderness. Requires lands recommended for wilderness designation to be managed as such until included in the National Wilderness Preservation System or released from consideration. Modifies land entry provisions to grant the Secretary of Agriculture authority over newly established national forest lands. Grants the Secretary authority to sell such lands as specified and other authorities over such lands. Title III: Transfer of Lands to the Bureau of Land Management - Transfers National Forest System lands within areas managed by the Bureau of Land Management to the Secretary of the Interior, withdrawing such lands from sale or disposal unless otherwise specified. Designates as conservation areas certain areas of newly established public lands known by a specific name. Amends the Surface Mining Control and Reclamation Act of 1977 to prohibit surface coal mining operations on public lands which were formerly part of the Custer National Forest. Amends the Bankhead-Jones Farm Tenant Act to grant the Secretary of the Interior authority over lands previously administered by the Secretary of Agriculture. Requires such lands to be eventually managed in accordance with the Federal Land Policy and Management Act of 1976. Requires the Secretary of the Interior to adopt the recommendations of the Secretary of Agriculture with respect to such lands which have been reviewed for wilderness suitability and to assess unreviewed lands for their possible designation as wilderness. Requires lands recommended for wilderness designation to be managed as such until included in the National Wilderness Preservation System or released from consideration. Authorizes the Secretary of the Interior to require deposits from purchasers of timber from public lands. Title IV: General Provisions - Sets forth which, if any, other designations and uses of such lands are affected by the interdepartmental exchange. Title V: Mineral Resources - Amends the Multiple-Use Sustained-Yield Act of 1960 and other Acts to empower the Secretary of Agriculture to administer National Forest System lands for multiple uses, including mineral claims and resources. Title VI: Transfer of O&C Lands - Transfers specified Oregon and California Grant Lands from the Bureau of Land Management to the Forest Service. Title VII: Severability - States that the provisions of this Act are severable.