The $p$-adic local Langlands correspondence for ${\mathrm{GL}}_2\left({\mathbb{Q}}_p\right)$ attaches to any $2$-dimensional irreducible $p$-adic representation $V$ of $G_{{\mathbb{Q}}_p}$ an admissible unitary representation $\Pi \left(V\right)$ of ${\mathrm{GL}}_2\left({\mathbb{Q}}_p\right)$. The unitary principal series of ${\mathrm{GL}}_2\left({\mathbb{Q}}_p\right)$ are those $\Pi \left(V\right)$ corresponding to trianguline representations. In this article, for $p\>2$, using the machinery of Colmez, we determine the space of locally analytic vectors $\Pi {\left(V\right)}_{\mathrm{an}}$ for all non-exceptional unitary principal series $\Pi \left(V\right)$ of ${\mathrm{GL}}_2\left({\mathbb{Q}}_p\right)$ by proving a conjecture of Emerton.