Please call 'scrollTo' method to scroll the specified row to the view.
componentDidMount(){
const row = this.state.data[8]; // the row to scroll to
this.setState({selection:row}, ()=>{
this.dg.scrollTo(row)
})
}
...
<DataGrid
style={{ height: 250 }}
ref={ref=>this.dg=ref}
data={this.state.data}
selectionMode="single"
selection={this.state.selection}
onSelectionChange={selection=>this.setState({selection})}
>
...