The rumen serves as a fermentation tank for bacteria to break down nutrients from feed for the benefit of the cow. Culture-dependent methods have identified the most prevalent genera as Ruminococcus, Fibrobacter, Butyrivibrio, and Prevotella. The objective of the study was to determine if the bacterial community in rumen fluid differed within a herd or across dairies within a given geographic region as assessed by a culture-independent method. In this study, rumen fluid samples from 82 cows across 4 different dairies in Washington were collected via stomach tube and filtered through cheesecloth. Cows within a herd were in the same pen and fed the same ration. DNA was extracted using the Qiagen QIAamp DNA Stool Mini Kit, amplified via PCR with primers targeting the V1-V3 hypervariable region of the 16S rRNA, and amplicons sequenced using an Illumina Miseq v3 paired-end 300-bp protocol for 600 cycles. Sequence reads were processed using the custom python application dbcAmplicons. Sequencing data at different taxonomic levels were categorized by percent relative abundance for each cow. The least squares means of the top 15 genera were computed and compared among dairies to look at bacterial population differences using Generalized Linearized Mixed Models (SAS v9.3). Significance was declared at P ≤ 0.05. Across all cows, Prevotella was the bacterial genus with the greatest relative abundance (44.8 ± 1.06), followed by Hallella (3.29 ± 0.11), Treponema (2.94 ± 0.15) and Paraprevotella (1.98 ± 0.06). Within a herd, the bacterial community of rumen fluid was similar among cows. However, each of the top 15 genera differed in abundance across dairies. These results suggest that cattle within a specific dairy have similar bacterial communities, but bacterial populations can differ across different dairies even within the same geographical region. Further work is necessary to determine the cause of the different levels of abundance of the top genera among dairies.