Searches for large extra spatial dimensions (LED) and extra neutral gauge bosons (P) in the dimuon channel are presented. Both of these searches are performed on $170pm11$ ipb of data collected at Fermilab's upgraded DO detector which studies ppbar interactions at a center-of-mass energy of 1.96 TeV. Although no LED or P signals are seen, 95\% confidence level limits are found in both cases. In the search for LED agreement between Standard Model backgrounds and data is shown in the dimuon mass versus ct spectrums. For the LED analysis a lower 95\% confidence level limit of $M{S} >$ 1.0 TeV (GRW) is obtained. In the search for P the measured high pt dimuon mass distribution agrees with the the predictions from the Standard Model. This P analysis finds and sets a lower 95\% confidence level mass limit of $M{Z'} >$ 690 GeV (SSM).