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At low radio frequencies (< 100 MHz), classical HII regions may becomeoptically thick (optical depth > 1) and can be observed as discrete absorptionregions against the Galactic nonthermal background emission created by Galacticcosmic ray electrons spiraling around magnetic fields. In this work we present74 MHz observations in the region 26>l>-15, -5<b<5, and report the detection of92 absorption features associated with known HII regions, and derive thebrightness temperature of the Galactic cosmic ray electron synchrotron emissionemanating from the column behind these regions. For the 42 HII regions withknown distances, the average emissivity of the column behind the HII region isderived. 74 MHz emissivity values range between 0.3 and 1.0 Kelvin per parsecfor a model assuming uniform distribution of emissivity. Methods for utilizingthis type of data to model the 3-dimensional distribution of cosmic rayemissivity and the possibility of using this method to break the HII regionkinematic distance degeneracy are discussed.Comment: Accepted, The Astronomical Journa

74 MHz Discrete HiiAbsorption Regions Toward the Inner Galaxy