diff --git a/proj4/proj4-tests.ts b/proj4/proj4-tests.ts
new file mode 100644
index 0000000000..c2d5a286b3
--- /dev/null
+++ b/proj4/proj4-tests.ts
@@ -0,0 +1,50 @@
+/// <reference path="proj4.d.ts"/>
+import * as proj4 from 'proj4'
+
+///////////////////////////////////////////
+// Tests data initialisation
+///////////////////////////////////////////
+const name = 'WGS84'
+const epsg = {
+    4269: '+title=NAD83 (long/lat) +proj=longlat +a=6378137.0 +b=6356752.31414036 +ellps=GRS80 +datum=NAD83 +units=degrees',
+    4326: '+title=WGS 84 (long/lat) +proj=longlat +ellps=WGS84 +datum=WGS84 +units=degrees',
+}
+const point1 = [-71, 41]
+const point2 = {x: 2, y: 5}
+const mgrs = "24XWT783908"
+
+///////////////////////////////////////////
+// Tests Measurement
+///////////////////////////////////////////
+proj4(epsg['4269'], epsg['4326'], point1)
+proj4(epsg['4269'], point1)
+proj4(epsg['4269'], epsg['4326']).forward(point2)
+proj4(epsg['4269'], epsg['4326']).inverse(point2)
+
+///////////////////////////////////
+// Named Projections
+///////////////////////////////////
+proj4.defs('WGS84', epsg['4326'])
+proj4.defs([
+  ['EPSG:4326', epsg['4326']],
+  ['EPSG:4269', epsg['4269']]
+])
+proj4.defs('urn:x-ogc:def:crs:EPSG:4326', proj4.defs('EPSG:4326'))
+
+///////////////////////////////////
+// Utils
+///////////////////////////////////
+// WGS84
+proj4.WGS84
+
+// Proj
+proj4.Proj('WGS84')
+
+// toPoint
+proj4.toPoint([1, 2])
+proj4.toPoint([1, 2, 3])
+proj4.toPoint([1, 2, 3, 4])
+
+// Point
+// WARNING: Deprecated in v3
+proj4.Point([1, 2, 3, 4])
\ No newline at end of file
diff --git a/proj4/proj4.d.ts b/proj4/proj4.d.ts
new file mode 100644
index 0000000000..70de08b5a6
--- /dev/null
+++ b/proj4/proj4.d.ts
@@ -0,0 +1,116 @@
+// Type definitions for proj4 2.3.15
+// Project: https://github.com/proj4js/proj4js
+// Definitions by: Denis Carriere <https://github.com/DenisCarriere>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+declare module "proj4" {
+    const TemplateCoordinates: Array<number> | InterfaceCoordinates;
+
+    interface InterfaceCoordinates {
+        x: number,
+        y: number,
+        z?: number,
+        m?: number
+    }
+
+    interface InterfaceDatum {
+        datum_type: number
+        a: number
+        b: number
+        es: number
+        ep2: number
+    }
+
+    interface Proj4Static {
+        forward(coordinates: typeof TemplateCoordinates): Array<number>
+        inverse(coordinates: typeof TemplateCoordinates): Array<number>
+    }
+
+    interface InterfaceProjection {
+        title: string
+        projName: string
+        ellps: string
+        datumCode: string
+        units: string
+        a: number
+        rf: number
+        ellipseName: string
+        b: number
+        a2: number
+        b2: number
+        es: number
+        e: number
+        ep2: number
+        k0: number
+        axis: string
+        datum: InterfaceDatum
+        init: typeof proj4.Proj,
+        forward(coordinates: typeof TemplateCoordinates): Array<number>
+        inverse(coordinates: typeof TemplateCoordinates): Array<number>
+        names: Array<string>
+        to_meter(value: number): any
+        from_greenwich(value: number): any
+    }
+
+    namespace proj4 {
+        /**
+         * @name defaultDatum
+         */
+        export const defaultDatum: string;
+
+        /**
+         * @name Proj
+         */
+        export function Proj(srsCode:any, callback?: any): InterfaceProjection;
+        
+        /**
+         * @name WGS84
+         */
+        export const WGS84: any;
+
+        /**
+         * Depecrated v3
+         * @name Point
+         */
+        export function Point(x: number, y: number, z?: number): InterfaceCoordinates;
+        export function Point(coordinates: Array<number>): InterfaceCoordinates;
+        export function Point(coordinates: InterfaceCoordinates): InterfaceCoordinates;
+        export function Point(coordinates: string): InterfaceCoordinates;
+        
+        /**
+         * @name toPoint
+         */
+        export function toPoint(array: Array<number>): InterfaceCoordinates;
+        
+        /**
+         * @name defs
+         */
+        export function defs(name: string): any;
+        export function defs(name: string, projection: string): any;
+        export function defs(name: Array<Array<string>>): any;
+
+        /**
+         * @name transform
+         */
+        export function transform(source: InterfaceProjection, dest: InterfaceProjection, point: typeof TemplateCoordinates): any;
+
+        /**
+         * @name mgrs
+         */
+        export function mgrs(coordinates: Array<number>, accuracy: number): string;
+
+        /**
+         * @name version
+         */
+        export const version: string;
+    }
+
+    /**
+     * @name proj4
+     */
+    function proj4(fromProjection: string): Proj4Static;
+    function proj4(fromProjection: string, toProjection: string): Proj4Static;
+    function proj4(fromProjection: string, coordinates: typeof TemplateCoordinates): Array<number>;
+    function proj4(fromProjection: string, toProjection: string, coordinates: typeof TemplateCoordinates): Array<number>;
+    export = proj4
+}