The damages sustained by reason of laying out, altering, or discontinuing any road may be ascertained by the agreement of the owners and the board of county commissioners or the board of township supervisors, as the case may be, and unless such agreement is made, or the owners in writing shall release all claim to damages, the same must be assessed in the manner herein prescribed before the road is opened, worked, or used. Every agreement and release must be filed in the township clerk’s office, when with a township, and in the county auditor’s office, when with a county, and precludes such owners of land forever from all further claim for damages. In case the board and the owners of land claiming damages cannot agree, or if the owner of any land through which any highway shall be laid out, altered, or discontinued, is unknown, the board in its award of damages shall specify the amount of damages awarded to each such owner, giving a brief description of such parcel of land in the award. The board having jurisdiction shall assess the damages at what it deems just and right to each individual claimant with whom it cannot agree. The board of township supervisors shall deposit a statement of the amount of damages assessed with the township clerk, and the board of county commissioners shall deposit the same with the county auditor. The auditor or clerk shall note the time of filing the same. The board in assessing damages shall estimate the advantages and benefits the new road or alteration of an old one will confer on the claimant for the same as well as the disadvantages. Any person living on land belonging to the United States who has made that person’s declaratory statement for the same in the proper land office, for all the purposes of this chapter, must be considered the owner of such lands.