The discovery of neutrino oscillations provides the first indication of a lepton flavor violating (LFV) process, one that isn't predicted by the Standard Model. As such, NOvA is part of a rich experimental program to constrain unknown parameters in the neutrino oscillation model, described for three neutrino flavors using the PMNS unitary matrix. It is a long-baseline experiment utilizing two detectors, a Near Detector at Fermilab and a Far Detector in Ash River, Minnesota for a total baseline of $\SI{810}{km}$. It receives a predominantly $\nu_{\mu}$/$\bar{\nu}_{\mu}$ beam peaking at $\SI{1.8}{GeV}$ from the NuMI beam facility at Fermilab. There are four oscillation channels used in the analysis, $\nu_{\mu} \rightarrow \nu_{\mu}$, $\nu_{\mu} \rightarrow \nu_{e}$, $\bar{\nu}_{\mu} \rightarrow \bar{\nu}_{\mu}$ and $\bar{\nu}_{\mu}\rightarrow \bar{\nu}_{e}$. With a total exposure of $13.6\times10^{20}$ and $12.5\times10^{20}$ protons on target for the neutrino and anti-neutrino beam modes respectively, $82$ candidates are seen in the $\nu_{\mu} \rightarrow \nu_{e}$ channel for a total predicted background of $26.8$ events. Similarly, $33$ candidates are seen in the corresponding anti-neutrino channel for a total predicted background of $14.0$ events. In the $\nu_{\mu}\rightarrow\nu_{\mu}$ ($\bar{\nu}_{\mu}\rightarrow\bar{\nu}_{\mu}$) channel, $211$ ($105$) candidates are seen with an expectation of $1156.1$ ($488.1$) events at no oscillations.

Consequently, this dissertation reports a measurement for oscillation parameters based on a joint fit for the spectra in these four channels, which is given by : $\Delta m^{2}_{32} = (2.41\pm 0.07)\times10^{-3}$ eV$^{2}$, $\sin^{2}\theta_{23} = 0.57^{+0.04}_{-0.03}$ (UO) and $\delta_{CP} = 0.82\pi^{+0.27\pi}_{-0.87\pi}$.

In addition, a leading $4.2\sigma$ confidence level of evidence is seen for $\bar{\nu}_{e}$ appearance. The oscillation analysis improves upon previous updates in several areas including particle identification, event reconstruction and cosmic background rejection. A principle component analysis (PCA)-based technique is also implemented for decorrelating important flux and cross-section systematics. In addition, new improvements are proposed in areas of energy estimation as well as confidence interval building.

NOvA is a long baseline neutrino experiment with an 810 km baseline, using the NuMIbeam at Fermilab, and a functionally identical near and far detector operating at an angle 14 mrad off axis from the beam. NOvA jointly measures muon neutrino (and antineutrino) disappearance and electron neutrino (and antineutrino) appearance to make a measurement of sin2θ23, δCP, and ∆m2 32, including its sign, the mass ordering. This dissertation reports a new measurement from NOvA, using 10 years of data, with a total exposure of 26.6 ×1020 POT of neutrino beam and 12.5 ×1020 POT of antineutrino beam. This represents 95.6% more neutrino beam exposure since the last NOvA analysis. Aspects of the analysis are discussed in detail, including neutrino energy estimation, analysis systematic uncertainties, including the implementation of systematics new to the NOvA analysis, and the Bayesian fit infrastructure using Markov Chain Monte Carlo (MCMC). The analysis yields the following credible intervals for the oscillation parameters assuming the normal ordering: δCP = 0.930+0.210 −0.290 π ∪0.150+0.150 −0.110 π, ∆m2 32 = 2.424+0.035 −0.040 × 10−3eV2, and sin2θ23 = 0.55+0.02 −0.06, with a 76% preference for normal ordering using a prior for sin2(2θ13) using Daya Bay’s measurement. If the Daya Bay sin2(2θ13) vs ∆m2 32 constraint is used as a prior instead, an 87% preference for normal ordering emerges.