ScrollRect.verticalNormalizedPosition

The vertical scroll position as a value between 0 and 1, with 0 being at the bottom.

using UnityEngine;using System.Collections;using UnityEngine.UI;  // Required when Using UI elements.public class ExampleClass : MonoBehaviour{    public ScrollRect myScrollRect;    public Scrollbar newScrollBar;    public void Start()    {        //Change the current vertical scroll position.        myScrollRect.verticalNormalizedPosition = 0.5f;    }}